The Vault of the Father

The Dray had a fault in her number three attitude cluster that made a sound like a spoon going round in a drain, and Garren would not fix it.

"Known quantity," he said. That was day two.

Day six, Leon asked again. The period was 11.1 seconds and he had begun counting it in his sleep, which he mentioned, and Garren said the same two words without looking up from the coolant manifold he was bleeding. Bearing race scoring. Sub-harmonic at 0.09 hertz. It had been in the log fourteen months and it had not moved a hundredth in that time.

Leon understood the argument. A fault you have listened to for six years tells you the day it changes. A fault you have repaired tells you nothing at all until it kills you.

He also understood that Garren had replaced the number two quad's entire actuator stack in eleven hours at Ninepenny with a torch and a borrowed jig, because that one had started walking — 0.4 hertz, then 0.6, then a bad hour at 1.1 — and a fault that walks is not a quantity. It is a direction.

Garren had a philosophy of maintenance built out of things he had watched go wrong for other people. He did not explain it. He had never explained anything.

So the spoon went round in the drain. Eleven seconds.

The ship smelled in layers. Hot dielectric off the port bus, which ran forty degrees warmer than the starboard because of a splice made in the eighties. Protein paste. And under both of them, permanent, the sour ghost of a water reclaimer that had processed the same forty tonnes for forty-one years and was not going to be shamed into improvement now.

Two thousand two hundred tonnes. Streaked to the beam line the colour of Veridus rust, forward frame to drive shroud — not corrosion. Sediment. A fourteen-month tidemark of a planet they had left and were not going back to.

Four holds. Three empty. One not.

Leon slept in the port acceleration couch on the bridge, harness loose across his hips, because it faced the boards. Lying flat somewhere he could not see the boards had become, over the past year, a thing his body declined to do. He had stopped arguing with it.

Garren slept in the engineering crawl on a folded pad, eleven metres from the reactor housing, at a measured 71 decibels. Leon had measured it. Garren had looked at the figure and said it was fine, and had gone to sleep in under four minutes, which Leon had also timed, because he timed things.

Eliana had taken the observation blister.

It was a bubble of scratched transparent aluminium on the dorsal spine, two and a half metres across, meant for a docking observer and stripped of everything but its bracket eighty years before either of them was born. It was fourteen degrees. It was also, per the environmental board, the best-ventilated volume on the ship — 0.9 air changes a minute against 0.3 in the berths — which was why she wanted it and why he had let her have it after ninety seconds of an argument he had lost in the first fifteen.

The blister was up a spine ladder. Six metres, twenty-two rungs.

It took her eleven minutes.

He had timed that too, once, on day four, from the bottom, out of sight, and then he had gone away and had not done it again. She climbed it twice a day. She did not ask for help and would not have taken it, and there was no version of offering that did not cost her something she could not spare, so he did not offer. He kept the deck below the ladder clear instead. That was the whole of what he was permitted to do about it.

She had made the blister hers with three objects.

A grey wool blanket, folded in eighths, which she sat on rather than under. Twenty minutes on bare deck plate made the bones of her hips ache in a way she had described once, flatly, as a sound rather than a feeling.

Pip's charging cradle, screwed into the bracket where the observer's console had been, its indicator throwing a small green square on the curve of the blister that slid as the ship moved.

And a chipped enamel cup, white, hairline crack running up from the base, which held nothing and had held nothing since Veridus. It had been in the galley of the flat above the Bellows. It had come with them. That was the entire argument for it, and it had won.

Nineteen days. Two checkpoints. He had the route in his head the way he had everything in his head, which was completely, and without permission.

The forgery took nine days.

He did most of it sitting on the deck of the bridge with three slates fanned around him and the number three cluster keeping time for a piece of music nobody wanted.

You do not forge a ship. You forge a history.

The Dray became the Ossuary Fen, hull registry PRV-4419-K, declared mass 2,180 tonnes. Twenty light. Every hauler in the arm under-declared by about one percent to shave berth fees, and a registry that came in exact was a registry a clerk looked at twice. Home port Callimach Ridge — a real agricultural moon in the second annexation ring, eleven thousand registered small carriers, a records office that had burned in year one of the occupation and been reconstituted out of tax returns. Half of Callimach's fleet did not exist. The other half could not prove that it did.

The cargo was the part he was proud of and the part he hated.

Two thousand one hundred tonnes of composted nitrate mash. Soil amendment, third grade. The stuff that goes to worlds where the topsoil has been shelled flat and somebody in a ministry has decided to grow beans again.

Nobody inspects it. Everybody smells it.

That was the entire design. Crack a hold seal on two thousand tonnes of mash and the smell gets into the officer's uniform and stays a week and does not come out, and he knows that, because it happened to a man he trained with. So he does not crack the seal. He stamps the manifest, steps back, and thinks about lunch.

Leon had run the reasoning three times looking for a flaw and had not found one. It was not a lie. It was an incentive.

He had bought the mash. That was the other thing. Eight hundred and ten marks out of a fund that could not spare eighty, loaded through a licensed broker in Ninepenny South against a real weighbridge ticket, because a hold that scans full and smells right and is full is not a hold you have to be clever about.

Cleverness was for the paper.

His father had used the same category.

Leon had found it first, before anything else, in the shipping annex bolted to the second file of the dead-man package. SYSTEM-OMEGA UNIT-02. Twenty metres of Gundarium Epsilon, a full-body Psycho-Frame, twin GN drives. Crated, moved two hundred and eleven light years under a manifest that read fertiliser plant, modular, disassembled, agricultural. Four hundred and six tonnes declared. Insured for nothing. Routed through three transhipment yards that all handled grain.

He had looked at that for a while. Then he had gone and bought composted mash.

You noticed what he did, he thought, the slate warm against his knee. You copied it. You are pleased with yourself.

It sat oddly. It kept sitting oddly for nine days. Somewhere in it was the fact that a man who built rescue frames for a thousand-year peace had been better at freight fraud than he had any business being, and that Leon had come by the aptitude the same way he had come by the eyes and the arithmetic, and that they had never once discussed it, and now would not.

Then he built the wear in.

A clean history is a forged history. Real ships take damage the way a coat takes a shape.

So the Ossuary Fen carried eighteen months of route log. A four-day hold at Trenneby Reach for berth congestion — true, publicly logged, and an inconvenience to two hundred other vessels. A nine-day layover at Pell Harrow that was not congestion. Nine days is too long for weather and too short for a refit. Nine days is a crew problem or a money problem.

He left it unexplained. An explanation in a route log is a thing a person wrote down on purpose. The absence of one is just a ship.

And a diverted leg out to Kosk and back empty. Eleven days gone, three thousand marks gone. Ships did that constantly, because somebody promised a load and then did not have a load, and the whole outer arm ran on people not having the load.

Then the maintenance log, which was where he put the truth.

Number three attitude cluster: bearing race scoring, sub-harmonic 0.09 hertz, first logged fourteen months prior. Deferred. Deferred. Parts requisition raised and cancelled twice, once for cost, once without a reason. All of it real. All of it audible right then, under the deck, doing what it said it did.

If anyone came aboard, the ship would agree with the paperwork. It was the only honest document on the vessel and it was the one that made the others work.

And a debt.

A ship with no debt is a ship with money, and a ship with money is interesting. So the Ossuary Fen owed 41,200 marks against her hull to a lending house on Callimach Ridge called Bergen & Sart, at nine and a quarter, balloon falling due in fourteen weeks. He wrote the loan instrument. He wrote two reminders, one polite, one less so, and left them in the master's correspondence folder unarchived, because a man being chased for money does not tidy the letters about it.

The debt did three things. It explained the thin margins. It explained a run into a war zone. And it made the master boring in the specific way that customs officers find restful, which is: a man with a problem that is not their problem.

Garren came through on the second day of it, wiping his hands.

"Who's Aden Corliss?"

"Master. Forty-one. Callimach-born. Hull-holder, up to his neck."

"Any good?"

"He's not good at anything. That's the point of him."

Garren looked at the slate for a second and went aft.

The crew was three, because the ship was three. You do not forge a crew of eight and then answer the door alone.

Garren went aboard under his own face, because his face was the face of a two-hundred-and-sixteen-year-old man with lattice-scarred lungs and a Directorate pension, and there was no improving on that with a lie. His papers said Garren Doss, retired, engineer. Everything in them was accurate except the last eleven years.

The third berth was listed supernumerary, unpaid, family. No name. No ident. No biometric file.

Leon went back and forth on that for two days. A name can be checked. An absence can be asked about. In the end: a broke hauler master carrying a relative for free was common enough to be invisible, and any officer who asked would get a story about a sister-in-law's boy and a bad situation at home, and would want it to stop before it finished.

He tested every document against the others eleven times. On the eleventh pass he found that the Kosk diversion overlapped the second Bergen & Sart reminder by two days, in a way that made the master look either desperate or stupid.

He left it in.

Checkpoint one was a picket sloop and a customs barge parked off the Ferrell junction, and it was nothing.

Four ratings and a warrant officer, eleven hours into a shift, sixty-one hulls processed by his own bored account. The warrant officer stood in the airlock with a slate and did not come further in. Two ratings went as far as the hold access, put a sniffer on the seal, read what the sniffer said, and came back with the faces of men who have just decided against a course of action.

Eliana was in the aft berth with the door dogged and a cannula in, four metres from where the ratings turned around.

Leon talked.

This was the part that frightened him. The fear was precise and it did not look like fear from outside. It looked like a tired hauler master leaning on a bulkhead.

The terror was grammar.

Kaelic Standard has a witnessed past and a reported past and they are not interchangeable, and the whole difference lives in one vowel. I loaded at Callimach — witnessed, I was there, I have made a claim about the world. It was loaded at Callimach — reported, I am telling you what I was told, and if it is false then I am a fool and not a liar.

Everyone in the annexed worlds mixed them. Everyone except people who had learned the language properly, in a school, out of a book, for a purpose.

Leon had learned it properly, in a school, out of a book. At the Academy on Zadkiel, where the corps taught the language of a nation nobody had fought in a thousand years because a curriculum committee thought it was elegant.

So he had spent four days on Veridus-9 un-learning it. Practising the mistakes out loud in an empty room. The wrong vowel in the second syllable of carried. The swallowed ending. Callimach had been annexed nineteen years ago and its Kaelic had come up off dockworkers, and dockworkers do not conjugate.

Say it right and you are educated. Educated is a question. Educated is where did you study, master, and then you are building a university on the spot, and every hall in it is a place they can send somebody to look.

"Where'd you load?"

"They loaded us at the Ridge." Reported past. Wrong vowel. Flat. "Sixteenth. I wasn't down there. I was arguing with a man about money."

The tone of a man handing over an excuse he expected to bore you. It bored him. The warrant officer's eyes went across it and off it.

"Discharge?"

"Hab Verrow, if they still want it. They wanted it in the spring." Small shrug. "Spring's gone."

Twenty-two minutes. He stamped the manifest, said something about the smell that was meant as sympathy, and asked at the hatch, as an afterthought, whether the master had heard anything about the tariff schedule shifting on third-grade amendment.

Leon said he had heard it three ways and believed none of them, and named a rate.

"That's what I heard too," the warrant officer said, with satisfaction, and left.

Garren sealed the lock. He stood with his hand flat on the wheel and did not turn round.

"You're too good at that."

Leon laughed, because that was the move. "You'd rather I was bad at it?"

"No." Garren turned. He looked at him for about three seconds, which from Garren was a speech. "I watched you do it to a bond clerk in Ninepenny. And to the doctor. And to a man on the Bellows floor about a shift you didn't work." The short dry cough. He swallowed it. "I'm not making a complaint. I'm making a note."

He went aft. The cluster said scrape.

Leon stayed in the lock a while with the smell of outside air still in it, and thought that Garren had left out the cellar. Then that Garren had left it out because Garren did not know about it. Then he stopped thinking, which was a technique he had got good at.

Orr's instruction had been written on the back of a dispensing slip because there had not been anything else.

0.4 bar equivalent. 60 min/day. Escalate no faster than she tolerates. Stop if she greys at the lips. She will not tell you when to stop. Watch her hands.

The Dray could not do 0.4 bar. What it could do was hold structural pressure and pull the oxygen fraction down until partial pressure matched what Meridian-7 would give her — 8.4 kilopascals against the 21 she had lived in all her life. That was the part that mattered. That was the part that hurt.

Same hour every day. On day three he had offered to move it later, so she could sleep through the recovery.

She had said no. That was that.

Day eleven. He came up the spine ladder and sat down on the deck plate opposite her, outside the folded blanket, because the blanket was hers.

She was sitting very upright with her back against the bracket. That was how you knew. When she was fine she slumped like anybody. At fraction she sat like a woman balancing a cup on her head, because getting air in at 8.4 required her ribs to be exactly where she put them, and slumping cost her four percent she did not have.

Twenty-two minutes in. Thirty-eight to go.

White cardigan, two sizes wrong, hole in the left elbow, sleeves pulled down over her knuckles. Pip in the cradle with its lights almost out and its fans idle, because it had read the room. Its cells held eleven percent less than a year ago. Leon had run the curve out to its intercept and had not mentioned it.

Her lips were not grey. Her hands lay on her knees, palms down, fingers spread. That was the tell. Spread meant managing. Curled meant finished, whatever she said out loud.

"Don't watch me." Six words on one breath, and the breath cost.

"I'm not watching you. I'm looking past you at a very interesting bolt."

"Which bolt."

"That one. Left of your head. It's the only bolt on this ship put in by somebody who cared."

She almost smiled. Talking was expensive, so she rationed it, and what she spent it on was mostly arguing with him. He had decided long ago that this was the highest use of her air.

So he talked instead. That was the deal, unspoken. He filled the hour with nothing so she did not have to fill it with effort.

He told her about the Kosk diversion he had invented and the eleven days it had cost a man who did not exist. He told her the galley paste had a batch date four years old, and that four-year-old paste and one-year-old paste were chemically identical, and that he found this personally offensive. He told her the cluster ran at 0.09 hertz, so five of them was fifty-five seconds, which was a minute if you weren't fussy, and she could use it as a clock.

She listened with her eyes half-shut. The signet had turned again, the way it always turned, the sunburst riding on the back of her thumb because her hands had got too thin to hold it where her mother had worn it.

At forty-one minutes she said, "Cold."

Fourteen degrees. He had a thermal wrap two decks down and she would not take it, because taking it meant a conversation about temperature that would become a conversation about circulation.

"When we get there," he said, "there's a habitat module. Sealed eighty years. Enriched air, actual heat. First thing I do, I go through every locker in that vault, and somewhere in it there is a coat."

"Mm."

"A real one. With a lining. And then—" and he heard himself start it and could not stop, because it was old furniture and his mouth walked into it in the dark "—and then once you've got real clothes we can start considering whether to treat you like an adult."

It had been funny when she was sixteen and came to the Blue Table in a borrowed jacket with the cuffs turned up four times.

It was not funny now.

Now it was a girl of twenty-two in a secondhand cardigan on a folded blanket in a fourteen-degree bubble, on a stolen course into enemy space, thirty seconds off the end of a rationed hour, with a bounty on her phrased as a marriage proposal. Adult had gone somewhere else entirely.

The joke hit the deck between them like a dropped tool.

He heard it land. He did not reach for it. Reaching would have been worse.

Eliana looked at him. Then she laughed — the real one, the small ugly one that came out of her chest wrong at low fraction and turned into a cough. She rode the cough down with her palm flat on her sternum and came back up with her eyes streaming, still laughing.

"Ow," she said.

"Sorry."

"No." She got a breath in. "Say it again in five months."

"I will."

"Say it when you've found the coat." Head back against the bracket. Fingers still spread. "It's better with the coat."

Nineteen minutes left. He counted the cluster. He did not count out loud.

Checkpoint two was the Halvern transfer station, day sixteen, and the officer who came aboard read.

That was the whole problem, and Leon knew it inside forty seconds, which was how long the man took to get through three screens of manifest without asking anything. A bored officer asks immediately, because questions are how you reach the end of a shift. A reading officer is quiet.

Sub-lieutenant. Kaelic Interior Service, not fleet. Revenue, not contraband. He was not looking for weapons. He was looking for money, and Leon rebuilt his entire approach in the time it took the man to sit down at the mess table without being asked.

He read for eleven minutes. Garren stood by the galley bulkhead with a rag in his hands and did not move.

Eliana was four decks down in the number two hold access void, in the dark, off oxygen, because the void had no environmental tap and running one to it would have shown on the board as an anomalous draw.

"Your Kosk leg."

There it is.

"Wasted eleven days," Leon said. Flat, sullen, reported past on the ancillary. "Man promised me seed press and then didn't have seed press."

"You went out empty and came back empty."

"That's what wasted means."

The sub-lieutenant did not react. He scrolled. "Your creditor sent a second notice on the sixteenth. While you were at Kosk."

"They send them every month."

"They sent two."

Leon let the silence do some work. "Yes."

He had planted the overlap as a decoy. That was the design: give a reader something small and shabby, so that finding it would satisfy the part of him that needed to find something. A man who catches you looking like a fool stops looking for a man who looks like a liar.

The sub-lieutenant had found it in eleven minutes and had been on it for four more, and he was not satisfied.

I built a hook for a small fish.

"I'd like the hold open."

"You'd like that for about ninety seconds."

"I've smelled amendment."

"Not two thousand tonnes of it."

"Master Corliss." The man set the slate down. Twenty-eight, maybe. Clean cuffs, which on that station meant he did not touch cargo, which meant somebody upstairs was watching him be thorough. "You went eleven days out of your way for a load that wasn't there. You're carrying third grade at a rate that doesn't cover your interest. There's a balloon against your hull in fourteen weeks." He turned a hand over. "I read a lot of these. Yours doesn't close."

He was right. That was the thing. He was entirely right. Leon had built the Ossuary Fen broke to make her boring and had overshot the mark by about four thousand marks a quarter.

"And your supernumerary. Family, no ident. I'd like to see them too."

Two ratings were already at the hold access with a seal cutter.

Fifty-one minutes. He knew it without checking, because the arithmetic ran whether he wanted it to or not, and four decks down his sister was folded into a two-metre void breathing 21 kilopascals of station air that would be down to nothing worth having in another twenty, and he could not think about that.

So he did the other thing.

Not a lie. He had no lie left that this man would eat. He gave him a number.

"You want to know how I make the payment," Leon said. "All right. I'll show you, and then you decide about my hold."

He put his hand out. After a moment the slate came across the table.

"Declared mass on lift from the Ridge. Two thousand one hundred eighty gross. Fuel state on that manifest, eleven point four percent of hull-max." He turned it round. "Now read my burn log. Halvern approach, two-stage retardation, and I've got fourteen point one aboard right now."

The sub-lieutenant looked at it. "You gained fuel."

"I gained three points on a two-thousand-tonne hull across a leg where I burned eleven. Ask me how."

"How."

"Because I bunkered at Trenneby against a Callimach-registered allocation. Trenneby prices under the second-ring schedule. I'm registered in the ring that subsidises it." Leon tapped the figure. "Six hundred and forty tonnes of subsidised propellant sitting in my tanks. At the Halvern differential — two marks eleven, off your own board this morning — that's thirteen thousand four hundred and forty marks of arbitrage I am currently flying around inside your customs area."

The sub-lieutenant's face did not change. Everything behind it did.

"That's a tariff exposure."

"That's a tariff exposure," Leon agreed. "It's also how I make my payment. And you've now got it in front of you at" — he glanced at the bulkhead chrono without needing to — "fifty-two minutes before your shift ends. Which means if you assess it, you're raising a cross-ring differential claim. A cross-ring claim needs a second signature from Revenue. Revenue on this station goes home at the hour."

The rag stopped moving in Garren's hands.

"Or you note the fuel fraction, you stamp me out, and I take six hundred tonnes of somebody else's subsidy off your station, and it stops being a number on your desk."

He did not say and you keep your clean cuffs. He did not say anything else at all. The offer had to sit there and be arithmetic and nothing but arithmetic, because the moment it became a bribe it became a crime, and the moment it became a plea it became a tell.

Thirty seconds. Forty.

The sub-lieutenant picked up the slate, went back to the fuel page, and looked at it the way a man looks at a road that has just got longer.

"Your Kosk leg is sloppy."

"My whole life is sloppy."

He stamped it. He called the ratings off the hold access with two words and no explanation, and at the lock he said, without turning, "Get your bearing race done, master. It's audible from the gantry."

"It's a known quantity," Leon said.

The lock cycled. Fifty-one minutes.

The void hatch was a manual dog. Four turns. It stuck at the third the way it always stuck and he put his shoulder through it.

Two metres by one and a half. She was folded into the corner with her knees up and her forehead down on her forearms. Pip lay on the deck beside her with every light off.

She had not made a sound in fifty-one minutes. There had been a rating standing a metre and a half above her head.

Her lips were grey. Her fingers were curled.

He got the cannula on her and got the flow up and said nothing.

He sat down against the bulkhead with his shoulder under hers, taking the weight, and watched the little cracked screen. Twenty-eight breaths a minute. Twenty-six. Twenty-four.

Pip came off the deck with a stutter in its port fan, put its cluster against her wrist, and did not sound the three tones.

Twenty-two. Twenty. Nineteen.

Her hand came off her knee and got two fingers into his sleeve.

That went on eleven minutes.

Then, into his shoulder, without lifting her head: "Did it work?"

"It worked."

"How."

"Fuel fractions."

She made a sound that was nearly the laugh. "Of course it was."

Meridian-7 came up on the forward screen on the morning of day nineteen, and it was rust and bone.

Not metaphor. Two colours and no third. The equatorial belt was iron oxide going brown at the terminator. The highlands were the pale grey-white of something left out in weather a very long time. Nothing between them. No green, no blue, no cloud with water in it.

The atmosphere read as a line one pixel thick at the limb, and the line was the wrong colour — thin, dun. Nitrogen, argon, and a spiteful trace of suspended dust that never settled because there was nothing to settle it.

No liquid water. The spectrometry had been unambiguous for eighty years, which was why the Concord had walked away from the survey installation and let it fall down.

They came around onto the dark side at 0620 ship time, and Leon watched for lights.

There were none. Not a beacon. Not a settlement glow. Not the pinprick of an automated relay. The night side was as black as the space beside it and the terminator was the only evidence that the planet was there at all.

Garren stood at the back of the bridge with a cup of something and looked at it a while.

"Nobody's going to steal anything," he said.

That was all he said.

The picket ran a thirty-one day sweep and they had come in on day nine of it. Twenty-two days of nothing. After that, a lifetime of counting to thirty-one.

Leon kept looking, and thought about his father.

Not warmly. He had lost the ability to do that somewhere around month four on Veridus and had not got it back, and had made his peace with the absence the way you make peace with a joint that no longer bends. What he had instead was narrower and more technical, and it went like this.

A man wanted a thing never to be found. He had the whole Reach — a thousand years of catalogued space, ten thousand worlds, moons and belts and dead stations by the hundred.

He chose a planet with no water, because water brings surveys back. He chose one with no strategic value, because value brings fleets. He chose one inside what would become enemy space, because nobody searches the middle of his own house. He chose a site that had already been abandoned once, because an abandoned site has a record on it that says nothing here, and a record like that is better than any lock.

He chose well. He sat down and worked out where a thing would never be looked for, and he was correct, and he did it years before there was anyone to hide it from.

Which meant he had known there would be.

Which meant he had looked at the same fifteen seconds of arc that Leon had looked at eleven days before the invasion, and had done the arithmetic, and had reached the right conclusion, and had told nobody, and had built a vault instead.

Leon put that away. There was a shelf now for things he put away, and it was becoming a substantial piece of furniture.

"Eliana." He keyed the intercom. "Blister. Ten minutes. It's ugly and you should see it."

A pause. A click. "Worse than Veridus?"

"Different kind of worse."

"Good."

He brought the Dray down out of the dark. Two thousand two hundred tonnes of forty-one-year-old hauler on a shallow entry that Garren had computed on paper, in pencil, because he did not trust the nav suite and never had — it drifted 0.3 degrees a day in yaw and had done since before either of them came aboard.

The thin air took her badly. At 0.4 bar there is not enough atmosphere to slow you and just enough to shake you. Skin temperature peaked at 640 Kelvin on the forward plates, which was nothing, and the buffet loading ran to 1.4 g lateral, which was not.

The hull began to talk in the low register. The number three cluster went scrape. Scrape.

Eleven seconds, all the way down through eighty kilometres of dust the colour of dried blood, toward a broken dome on a plateau where nothing had moved in eighty years.

Meridian-7 took four breaths off her and gave one back.

Eliana had known it would. She had read the survey brief twice on the way down, all eleven pages, including the annexes nobody reads, and she had done the arithmetic that mattered to her and to no one else aboard. Surface pressure 0.41 bar at the observatory plateau. Oxygen fraction 0.203, which was almost funny — almost breathable, the way a knife is almost a spoon. Partial pressure at the mouth, eighty-three millibars.

On Astraia it had been two hundred and twelve. On Astraia she had needed a chair after crossing the long gallery.

So: eighty-three. She had the number before the ramp came down. She had it the way she had the number of stairs in every building she had ever lived in.

The ramp came down and the cold came up it.

Not the cold of a winter. The cold of a thing that had never been warm and had no memory of warmth anywhere in it. It went through the thermal shell, through the cardigan under the shell, and sat against her ribs like a hand laid flat. She stood at the top of the ramp with two fingers on the rail and let it happen. Her breath fogged the inside of the visor and cleared and fogged.

Right, she thought. Hello.

The harness was the humiliation. It always was.

The Dray carried three Concord surplus rebreather rigs, forty-one years old, sold off in a job lot when the outer-ring stations were struck. They were built to a specification that assumed a body. MINIMUM RATED MASS 62 KG, stencilled on the yoke in paint that had survived four decades because nobody had ever needed to argue with it. The rig put a nine-kilo bottle across a sternum plate, two shoulder straps and a waist band, and it did this by counting on the wearer to have a chest that would stop the plate travelling.

She was twenty-nine point four that morning. She had weighed herself in the medbay with one hand on the bulkhead, because she liked knowing, and because not knowing was worse.

Garren had punched four new holes in each strap with a leather awl he owned for no reason she had ever established. Then two more. Then he had cut the strap down and reworked the buckle out of a length of cargo webbing, and it still was not right. The plate rode. It came up as she walked, and by the fortieth pace it was under her chin, and she had to reach in and push it down, and the pushing cost breath, and the breath cost distance.

The regulator was worse than the harness and better hidden.

It was a demand valve. It opened when the wearer pulled on it — when pressure inside the mask fell by four tenths of a kilopascal, a diaphragm cracked and the gas came. Four tenths of a kilopascal is nothing. It is a child drinking through a straw.

There were mornings she could not make it.

Garren had found the adjustment on the second day out and turned it without discussion, down to the bottom stop, the setting with a small stamped C beside it. C for casualty. The setting you used on somebody unconscious, whose chest was moving but not intending anything by it. He had turned it, tested it against his own palm, handed the mask back and said, "Cold up there. Bring the coat."

"I don't have a coat."

"I know."

Now the valve cracked on almost nothing and gave her her gas, and every time it opened with that small dry tick she heard the letter stamped beside it.

Fine, she thought. I'll take it.

She had turned the arithmetic into a rule, because a rule can be obeyed and a fear cannot. Twelve paces, then stop. At rest her draw ran a shade under two tenths of a litre a minute. Walking on the flat, in the shell, on rising ground at 0.4 bar, it went to six tenths and stayed. The bottle was three point two litres charged to two hundred bar. Six hundred and forty litres of free gas. She carried one and Garren carried the spare, and that was the arrangement they had all agreed to and nobody had ever described out loud as what it was.

Six hundred and forty over six tenths. One thousand and sixty minutes sitting still. One hundred and seventy-eight moving.

Two hundred and forty metres from the crawler to the observatory's collapsed south face. Twelve paces was about nine metres. Twenty-seven stops.

She did it in thirty-one, and she did not let either of them count.

The observatory had been dead about eighty years, and it had died the way buildings die when nobody kills them.

The dome went first. Sixteen metres across, riding a bearing ring, and the ring was still up there — a circle of machined steel four metres above the floor with the tooth pattern of a drive gear cut into its inner face and not one tooth chipped. Inside it there was sky. The panels lay in the yard in a shape that told you exactly how it had come apart. Not blown. Not struck. Fatigued. A seal had gone, then a hinge, then the whole north quadrant had folded inward under its own weight one night when the temperature dropped forty degrees in three hours — the way it did here every night, and had done every night for eighty years, with nobody watching.

Dust over all of it. Not shed dust. This dust had never been wet. Never rained on, never condensed on, never walked through by anything with feet. It took their bootprints like fresh snow and it would hold them, she thought, until something knocked the building down.

She went in slowly with one hand on the frame and looked at the room the way she looked at everything, which was the only skill she had that cost no oxygen.

Astrometric survey station. She knew before she found the plate. The mount in the centre of the floor was equatorial, polar axis set for a latitude nobody on the crew would care about, fine-motion worm drive still in its housing with the grease gone to grey chalk. Wide-field work. Long exposures on a driven mount, night after night, cataloguing. Someone had come out here to count stars and write the count down.

The instruments were gone. Not looted — decommissioned. Looters take the mount as well, because the mount is metal. These had been unbolted properly, the bolts backed out and left in a tin on the shelf, the cable runs cut at the gland and the glands capped. Somebody had shut this place down on a schedule with a checklist in their hand.

And then, on the wall by the plate store, at the height of a person sitting on a stool, someone had painted a small constellation. Badly. With a brush far too wide for the job. Under it, in block capitals: OUR ONE. An arrow pointed to one star in it. The arrow had been drawn twice, because the first one had gone in wrong.

Below the paint was a shelf. On the shelf was a ring the exact diameter of the bottom of a mug, burned into the varnish by eight decades of somebody putting a hot mug down in precisely the same place.

She stood and looked at the mug ring for a while.

Nobody had come here in a hurry. The Concord had run its numbers on the outer ring, found the outer ring wanting, and sent a letter. Someone had read the letter and then finished the observing run — she could see that too, three empty plate holders stacked and one still loaded — and then packed the bolts into a tin, and pulled the door to, and in the twelve minutes between the door and the transport had not gone back for the mug.

"Anything?" Garren said behind her. His voice came flat and small out of the mask pickup. He was on the same rig she was and it did not agree with him either. Thirty years of lattice dust had left him a set of lungs that made a noise on the intake like a drawer opening.

"They loved it," she said.

"What?"

"Whoever was here." She lifted one finger toward the paint. "They loved it, and then head office sent a memo."

Garren looked at the constellation for a long moment.

"Bad brush," he said.

"Terrible brush. Look at the arrow. He drew the arrow twice." She let a breath go, took another, and the valve went tick. "I like him. He was very bad at this and he did it anyway. That's my sort of person."

"Explains the company you keep."

"It explains the whole family, Garren."

Something happened at the corner of Garren Doss's eyes that on another man would have finished as a laugh. It got as far as the skin and stopped, the way everything did with him, and he turned and went to look at the floor.

Pip came in after them, and Pip was not enjoying Meridian-7 either.

The drone was built for a pressurised ward. Four ducted fans, forty-one millimetres, sized against a standard cabin atmosphere, and here they had four tenths of the air to push. It compensated the only way it could, which was revolutions. Nominal hover, eighteen thousand rpm. It was holding twenty-nine and a half and the pitch had climbed with it, up out of wasp-in-a-jar and into something thinner, a note that lived near the top of her hearing and made the fillings in her back teeth feel involved.

It could hold station. It could not hold it long. Every ninety seconds it landed — on her shoulder, on the sternum plate, on the bottle yoke, wherever it could get purchase — and sat with its lights dimmed to nothing while the cell recovered.

The cell was six years past its service interval. At the last check it took charge to sixty-one percent of rated capacity and shed a further point every eleven days. It recovered less each time.

She reached up without looking and put one finger on its shell, and it pressed back, which was not a behaviour anyone had programmed into it, and which she had stopped mentioning to people years ago.

The coordinates in her father's package were good to eleven metres.

Leon had said so on the way down, in the flat voice he used for numbers, which was the only voice of his she completely trusted. Eleven metres, ninety-five percent, on a fix taken who knew when with equipment that had since been vapourised in orbit over Astraia.

Eleven metres is nothing. Eleven metres is a room.

It took four hours.

Because eleven metres in three dimensions is a sphere of five and a half thousand cubic metres. Because the building had two floors and a sub-floor and the sub-floor had gone in at two places at least. Because the fix was referenced to a survey benchmark that was a brass plug in a concrete pad, and the pad had cracked and moved some unknown distance in eighty years of forty-degree nights. And because everything, everything on this planet, was the same colour.

That was the part nobody warned you about. Rust and bone. The rock was rust and bone, the dust was rust and bone, the concrete had weathered to rust and bone, and the only black thing in the world was shadow, and the shadows were cut-paper sharp because there was no air to soften them. You could not see a seam. You could not see a joint. You found edges by putting your hand on them.

She helped for the first hour. After that she helped less.

The rule broke down. Twelve paces and stop works on the flat. It does not work on rubble, where every step is a decision and some of the decisions are wrong, where crouching to look under a slab means getting up again afterward, and where getting up from a crouch has been a project since you were fourteen. Her draw went past six tenths and did not come back. The gauge on the back of her left glove did what gauges do, which is fall at a perfectly steady rate and feel like it is accelerating.

Under the glove her thumb ring had turned again. She could not see it and did not need to. The sunburst sat on the back of her hand where her mother had always worn it, and it was loose enough now that it turned on its own.

At two hours forty she sat down on a fallen dome panel and stopped pretending.

At three hours ten Leon came past her for the fourth time with a pry bar over his shoulder and said, "You could wait in the crawler."

She looked up at him.

He had his visor up. Leon, being Leon, had spent an hour of the descent establishing that at 0.4 bar on a positive-pressure feed he could run it open and lose maybe three points of saturation, and he was right, he was always right, and it meant she could see his whole face while he said stupid things to her.

He was not angry. That was the thing. He was four hours down inside a problem, cold, with his father's handwriting in his chest pocket and eleven metres of confidence that had turned out to be a lie, and she had become an item on a list of things that were not going well.

"You could wait in the crawler," he said again, "instead of sitting in the middle of the search area."

"Say the rest of it."

"There isn't a rest of it."

"There's always a rest of it." She took the breath for the next part and spent it carefully. "You want to say: you're burning gas and you're not finding anything. Which is true. So say it, I'll agree with you, and then you can go back to being wrong about where the door is without me watching."

Thirty metres off, Garren did not look up. Garren had a genius for not looking up.

Leon's jaw moved. "Eliana—"

"When I've got a coat that fits," she said, "we'll consider talking to me like an adult. I know. It's been years. I've made my peace with the schedule."

He stood there with the bar on his shoulder.

Then he took it and went and put it through a floor.

That was how they found it. She decided, watching him do it, not to tell him — he would have enjoyed it far too much and she was not in a mood to give him anything.

The bar went through the sub-floor at the north-east corner of the plate store, where decking had been laid over joists and the joists had been ruined from below by eighty years of nothing at all. No water. No rot. Only cold, cycling, opening the grain and closing it, twice a day, fifty-eight thousand times.

The decking dropped into a void that had no business being there. Under the void, a stair of eight steps. Under the stair, a floor of poured composite that was not eighty years old and had never been any part of the observatory.

And in the floor, the door.

She got down last, on Garren's arm for the steps, which she permitted because there were two people present and one of them was Garren and there was a rule about that. Eight steps. Four stops. She was not proud of it.

Then she saw the slab and forgot to be anything.

Three metres by three, near enough, set flush, with a shadow gap of about four millimetres all the way round. It was the only clean surface on the planet. Eighty years of a building coming apart overhead and not one grain of dust on it — which meant the gap was not a gap, which meant it was sealed, which meant there was a mechanism under there that had been holding a seal since before she was born.

Garren crouched, put a hand near it, and did not touch it.

Leon ran the sounder across it twice and read off the return. "Nine hundred millimetres. Layered — that's a composite section, four strata, and the top four hundred comes back at about nineteen thousand kilos a cubic metre." A pause. "That's a Gundarium analogue. That's armour."

"Weight," said Garren.

"On this gravity, eighty-one tonnes. Call it eighty-four with the collar."

Garren looked up — at the void, and the fallen floor over the void, and the ruin over that.

"Heavier than the house," he said.

"Heavier than the house," Leon agreed.

No handle. No panel, no keypad, no reader, no seam suggesting a hinge. One thing only, in the centre of the slab, the size of a coin: a recess, and in the recess a fine grille, and behind the grille nothing she could see.

Eliana knelt beside it, which took a while, and looked in.

Not a microphone. Not exactly. Seven concentric rings inside, machined, each cut to a different depth. A resonator. A thing for measuring the shape of a sound and not the meaning of it.

Her father had built a lock that did not care what you said. It cared how the air left you.

Leon crouched on the other side of it. "He wrote one line in the log. 'The door opens to the family name, spoken properly.'" A pause. "That's the whole line."

"Astraia," Eliana said. In Standard, through the mask, flat, because she had known this was coming since the moment she read the coordinates and had carried it down the stair with her along with everything else.

He tried first.

Of course he tried first.

He took the mask off — he had eleven minutes of clean speech in him at this pressure before it started costing, he had done that sum too — and knelt over the aperture and said it.

"As-tray-a."

Flat. Two hard consonants and a diphthong in the middle where something else entirely belonged. A Standard mouth doing a Standard thing. A name shaped in the front of the face.

Nothing.

"Astraia." Stress on the second. Then the third. The third was nearer. It was still wrong.

"Ast-rah-ee-a." Four syllables. He had got the count right, the way you get a thing right by measuring it. A drawing of the word.

He shut his eyes and set his jaw the way an athlete sets a shoulder, and tried once more.

"Astraia."

The fourth was the worst, because it was almost. He held the low placement about a third of a second and lost it, and the sound skidded up into his nose and stopped. Eighty-one tonnes did nothing.

He knelt with his hands flat on the slab and his mask in one of them.

Their mother had taught him this word from the time he was four. That's a nice word, love. It isn't ours. At eleven she had stopped, and laughed, and touched his hair, and said everybody gets one thing, and started teaching Eliana instead, because Eliana was ill and in bed and there was time.

He had carried it fourteen years, folded small.

"Leon," she said.

"I know."

"Leon."

"I know." Not a shout. He got up, turned half away, put the mask back on, took two breaths off it. Then, in an entirely reasonable voice: "It's yours. Go on."

She had to take the mask off.

She had known that for four hours and had not let herself look at it, and now she looked, quickly, the way you look at a bill.

Off the feed, at 0.41 bar and 20.3 percent, she would be breathing eighty-three millibars. Her saturation on enriched gas sat at ninety-four, and she had bought that number with a very great deal of sitting still. Off it, at this pressure, it would fall. She had no way to know how fast, because nobody had ever built the curve for a body like hers. So she guessed. Twenty seconds before her vision started closing from the edges. Forty before the shaking made her voice useless — and she had to be done before the shaking, because the shaking would put a tremor on the vowel, and the vowel was the entire point.

Twenty seconds. Say it in ten. That was the budget.

She breathed off the mask for two minutes first, deliberately, running her draw as high as she could make it, which was not high. Loading the tank. Leon watched the gauge on her glove and said nothing whatsoever. Garren stood at the foot of the stair with his back to them both, looking up at the dark, doing the one useful thing available.

Pip came down onto the sternum plate and dimmed to nothing and stayed.

Then she pulled the seal and the mask came off her face and Meridian-7 got in.

It was not like drowning. She had been told her whole life it would be like drowning, and it was not. Drowning has water in it, and water is a thing. This was the opposite of a thing. The room had been taken away from around her mouth. She breathed in and there was volume and no substance, an enormous nothing filling her, cold enough to ache in her back teeth, and her body took it and reported honestly that it had received almost none of what it had asked for.

The count started in her head. She did not start it. It started.

She put her hands on the slab. It was cold enough to hurt. She leaned her weight onto them and got her chin over the aperture.

Three.

Her mother's voice. Not saying the word — saying the instruction, ten thousand times, over a bed, under a yellow lamp, with the window open on a warm night on a planet that no longer existed. Lower down, sweetheart. Not the mouth. The mouth is where the language ends up. Start it under.

Five.

The Astraian court vowel is not made where Standard vowels are made. It does not live behind the teeth or in the palate. It opens at the root of the tongue with the throat wide and the larynx dropped, and it is not pushed — it is allowed. A column of air let go and shaped on the way past. It comes out low and doubled, a second tone underneath the first that you do not produce so much as fail to prevent. Standard speakers hear it and think it is a long A. It is not a long A. It is a room with two people singing in it.

Leon's throat would not do it. He made the sound in his mouth, and the mouth is the wrong instrument.

Seven.

The corners of her vision had gone soft already, ahead of budget.

Pip lifted off the plate and gave the distress call. Three rising tones. Pause. Three rising tones.

She dropped the larynx. She opened the back of her throat until it felt like a yawn she was not permitted to finish, and let the little air she had climb up out of her, and did not push, because pushing was the one thing that would ruin it, and because there was nothing left to push with.

"Astraia."

Low. Doubled. The third syllable opened under the second and held exactly as long as it was supposed to hold and not one beat longer, and the last vowel closed the way her mother closed it — softly, downward, like a door pulled to by someone who does not want to wake the house.

First time it had been said properly since a corridor with a two-berth pod at the end of it and a hand over her eyes.

The resonator heard it.

A click under nine hundred millimetres of laminate. Very small. Then a second. Then something enormous let go of something else enormous.

The slab sank. Not a swing, not a slide — straight down, four hundred millimetres on a central column, with a hiss as eighty years of held atmosphere equalised, and the air that came up out of it was eleven degrees warmer than the air in the room and smelled of nothing at all. Then the whole column rotated ninety degrees on its axis and withdrew into the shaft wall. Eighty-one tonnes at the speed of a person walking, silently, on a mechanism that had sat in the dark under a dead world waiting to be spoken to.

She had the mask back on her face at nineteen. The valve went tick and the gas came.

Garren's hand was on her bottle yoke. She had not felt him cross the room. He read the gauge, turned it, read it again, and let go.

The three of them stood at the lip of it.

The shaft went down. Not a stair — a shaft, four metres across, maintenance ladder on one side, cargo track on the other, gauge wide enough to lower something the size of a house down it in pieces. Garren's lamp gave out at forty metres.

For a moment there was nothing.

Then, a long way below, a light came on.

Not the whole thing at once. One level. A ring of low standby lamps, amber, the colour every dormant system in the Reach had ever used to say I am here and I am not doing anything yet, and it lit a landing and a rail and a section of composite wall, and held.

Three seconds. Another ring, further down, smaller with distance.

Three seconds. Another.

They came on one level at a time, going away from her, each smaller and dimmer than the last, and she counted, because counting was what she had. She got to eleven before the lowest was too small and too far to be sure of — a single amber point at the bottom of a hole in a dead planet — and she thought it might have been twelve.

Her father had built this. Shipped it out on a forged agricultural manifest, buried it, gone home, eaten dinner, said nothing to anyone for years. And set the lock to a word he could not pronounce either — she knew that, she had heard him try, he had been nearly as bad as Leon.

So he had known exactly whose mouth would have to open it. And when.

Beside her, Leon was breathing too fast. She did not look at him. She could hear it.

Garren said, "Well."

The gas came, tick, and came again.

There were things she could have said, and she had them all at once, in order. He knew I'd be standing here. Or: Say something, Leon. Or the true one, which had arrived while the lights were still coming on and had gone in like a splinter — he built a door only I can open, and then he never once told me what was behind it, and he had twenty years.

Speaking through the mask meant lifting the pickup, pressing the plate, and drawing enough breath to carry a whole sentence. She did not have a whole sentence in her. Everyone standing on that lip knew it.

So she said nothing, and let the mask be the reason.

She was glad of it in a way that made her eyes sting, and she let that be the cold.

The shaft went down sixty-one metres and the hoist took three minutes and forty seconds to do it, and Leon counted every one of them.

He did not mean to. The counting happened the way it always happened, underneath everything, a second process running in a room he did not have the key to. Three minutes forty at a nominal 0.27 metres per second. The platform was rated four tonnes and had been built for crates, not people, and it swayed on its guide rails with a slow lateral period of about two seconds, which meant the rails had gone out of true somewhere in eighty years of nobody.

The lamp on Garren's chest rig threw the shaft wall past them in bands. Cut rock. Then poured composite. Then cut rock again where the drill had found something it did not like and the crew had shrugged and gone around.

"Cold," Garren said.

"Minus nine at the head. Colder at the floor."

"That's warmer than the surface."

"By four degrees. It'll feel worse. There's no wind down here to compare it to."

Garren made a sound that was neither agreement nor disagreement and coughed into his sleeve, twice, controlled, the way he did everything. Thirty years of lattice dust, metered out one breath at a time.

The door had opened an hour ago. Leon had stood in the ruin of the observatory with the collapsed dome making a broken bowl of the sky above him and had said the word four times, four different ways, all of them wrong, and the panel had done nothing at all. Not refused him. Not even that.

Then Eliana had lifted the breather off her face and said it once — three syllables that went somewhere in the back of her throat that his throat did not have — and eighty tonnes of rock had moved.

Astraia.

She had said nothing about it afterward. That was the part he kept turning over. She had put the mask back on and looked at the open dark and had not made the joke that was sitting right there in front of her, wrapped and waiting, about his accent.

The platform came down through the last four metres and the lamp stopped finding walls.

The vault was a hundred and ten metres on the long axis, and he knew that before he had seen the far end of it, because the hoist clamps came home and the echo returned in six hundred and forty milliseconds and sound in this air at this temperature moved at about three hundred and twenty-five metres a second. He had not chosen to do that arithmetic either.

Pressurised. That was the first real thing. Point eight two bar against the surface's point four, oxygen up around twenty-four percent, and Leon knew it because his chest stopped doing the small tight work it had been doing for six days and simply breathed. He had not understood how much of himself he had been spending on that.

The lamps came up in banks, north to south, each one taking half a second to strike and then holding. The sequence took eleven seconds to reach the far wall. Leon stood on the platform with his hand on the rail and watched his father's electricity wake up under a dead world.

Everything was grey and everything was rimed. Frost lay on the floor in a crust perhaps two millimetres deep, all the water this room had ever had, precipitated out and given up. Not eighty years of it. Twenty-two, maybe twenty-three, since the air in here last had anything to lose.

Racks down the east wall. Ingot stock, banded, standing on end like a library — thirty-one tonnes of it by the manifest plate, titanium-aluminide, gundarium precursor in the green bands, the good ceramic feedstock sealed in drums with Concord hazard flags that had faded from orange to a sort of apricot.

The fabrication cell squatted in the middle of the floor under a shroud, four metres by nine, and it was the single most expensive object in the room that was not the other thing.

And along the west wall: crates.

Forty of them. He counted without deciding to. Agricultural stencils. GRAIN, SEED — HARDENED VARIETALS. MERIDIAN SURVEY CO-OP. A bonded-warehouse mark from Callis, from a firm that had gone under the year Leon turned eleven.

He put his glove on the nearest seal and it cracked with a small hiss, the pressure inside a little higher than the pressure outside, because the man who packed it had assumed a slow leak over decades and had overfilled to compensate. Two percent, probably. He would have calculated it.

Ration bricks. Two hundred and forty. Vacuum-dense, thirty-year shelf life, the kind that tasted like the inside of a filing cabinet.

Next crate. More ration. Then water reclaim cartridges, sixty of them, each good for four hundred litres. Then a heater — a real one, resistive core with a ducted blower, forty-eight kilos, four kilowatts, the kind you bolt into a hangar and not the kind you put in a house.

Then medical. Four crates of medical.

Leon opened all four and stood there reading labels with his breath going up past the lamp.

Stabilisers. Not Tessamine — the generation before it, an inferior formulation, sixty percent of the work at best. Twelve months of doses.

The dosage schedule was printed on the case lid. It was by body mass. His father had ordered against a mass of thirty-one kilograms.

That was the paediatric column.

It was also, this morning, correct.

He closed that crate carefully and stood with his hand flat on the lid for a moment and then took the hand away.

The last crate on the end was smaller and had no stencil. Inside: a habitat control head in shock foam, a spare fan assembly, and wedged along one wall to stop the rest from shifting, a flat parcel in shop wrapping.

He opened one corner of it with two fingers.

A coat. White wool. The tag was still on, printed in Reach marks, from a shop on the Third Concourse that had been under the Ring when the Ring came down. Girl's twelve.

It would fit her.

He folded the wrapping back down, set the fan assembly on top of it, closed the crate and pressed the seal until it took.

"Anything?" Garren called from over by the cell.

"Rations. Water. Meds."

"Good meds?"

"Old meds."

He walked away from the crate and did not look at it again, and the not-looking took effort, the way carrying something up a slope takes effort.

The habitat module was set into the north-west corner: nine metres by five, a real door, a real airlock, four bunks. He put his head in. It smelled of nothing at all. The atmosphere panel had been left programmed and the programme had a name on it.

E.Z. — 1.00 bar / O2 30% / T 22C / humid 40%

Under it a second profile, unnamed, at standard.

One profile had a name.

He set the room for you. Leon stood in the doorway with his hand on the frame. And he never once meant for you to be in it.

He held both halves of that and could not make them meet, so he stopped trying and went back out onto the floor.

The tarpaulin was the size of a tennis court and had gone the colour of the frost. Garren pulled the corner release and eleven hundred kilos of laminate slid off in one long collapsing wave and lay on the floor like something shot.

Leon had been raised in the Reach. He had crewed mobile suits since he was nineteen. He had watched a Kestrel-class lift a hundred and forty tonnes of ferry hull off a family of four with hands designed by a committee that had spent nine months arguing about finger padding.

Every mobile suit he had ever stood under had been built to get people out of things.

This one was not.

Nineteen point eight metres to the crown. Twenty-four point one across the shoulders with the emitter housings folded, which they were, laid flat along the spine like a bird with its wings shut. It stood in a gantry cradle with the knees carrying an eleven-degree bend, because a frame at this density could not be racked straight without setting a bending moment into the femoral spar that somebody would have to anneal out later.

His father had known that. He had built the bend into the cradle at the design stage and had not written a note about it anywhere.

Dry mass forty-one point six tonnes. It said so on the cradle plate. Leon did the addition anyway — battery charged, cleaver mounted, six funnels racked, injector reservoir wet, coolant to level.

Forty-eight point two.

A Kestrel came in at thirty-one and could throw a shipping container across a rail yard.

The armour was the wrong colour. His hands understood that before his head did. Gundarium Epsilon should be a warm grey with a bluish grain under work lamps. This was almost white and it took the light and gave nothing back — four hundred microns of nano-laminate doing exactly what it was for, which was denying a targeting laser a clean return.

Thirty-four millimetres on the chest glacis. Twenty-two at the shoulders. Eleven on the thigh interiors, because you saved mass in the places where a hit meant the argument was already over.

Threaded through all of it at a one point two millimetre pitch, invisible, the micro-repair lattice. It fed off a ninety-kilo sacrificial reservoir in the lower back and would close a forty-millimetre fracture at about six millimetres an hour.

It would not, under any circumstance, grow back an arm.

He walked the length of it and read it the way he had been trained to read a machine, which was the way you read a person you are going to have to work with.

Twin GN drives, port and starboard, a one point four metre torus each, seated in the dorsal cage behind shutter assemblies with fourteen individually actuated leaves. Eighteen megawatts continuous apiece. Twenty-six for ninety seconds with the leaves full open, after which the dorsal strakes stopped rejecting heat faster than the drives made it and the whole rear thorax began to cook.

Between the drives, filling the lower chest, the photon battery. Two point two metres by one point one, matte black, cased in something Leon did not recognise and would have to look up.

The battery answered a question nobody in the Reach had ever thought to ask, which was: what if you wanted more power than you could generate, for nine seconds, and did not care what it cost you afterward.

One point one gigawatts on the dump. Three hundred and forty seconds to refill off both drives with nothing else drawing.

Three hundred and forty seconds. In a fight that was a geological era.

The Wings of Light emitter rails lay folded along the spine. Three point one metres closed, nine point four deployed. Minovsky projection hardware, overcharged past every rating the Reach had ever published, holding a coherent plane out to eleven hundred metres.

Eleven hundred metres of edge.

Leon stood under the shoulder and thought about a kilometre-long knife and what it would do to a hull, and then — he could not stop it — about the crew complement of a Kaelic line cruiser, and the answer arrived instantly and was no use to anybody.

Six fin funnels in a spine rack. One point nine metres each, three hundred and ten kilos each, independent thrusters, independent emitters.

No control lattice fitted. The mounting seats were bare metal.

Left hip, mag-lock: the cleaver. Eleven metres of blade, nine hundred and eighty kilos, in a transit cover with a hazard band still zip-tied at both ends. At forty-four kilohertz it would not cut a warship so much as persuade a warship to stop being one object and start being two.

Right hand: a supercritical injector, the port dead centre of the palm, ringed with hardened lands so the hand could close on armour and hold it while it emptied.

You had to touch something to use that. You had to put your hand flat on it and hold on while it happened.

Who designs that.

The head had no face. A sensor band, two hardpoint clusters, a vertical seam where the intake cowling met the crown. It was not a face and his eye kept making it into one.

He climbed the gantry to shoulder height because his legs did it without asking. From up there, level with the emitter housings, glove on the cold rail, he could see down through the open cockpit hatch at the thing he had come sixteen hundred light years and fourteen months to look at.

The Psycho-Frame.

It was not a component. It was the entire interior surface of the cockpit, floor to crown, a lattice grown rather than machined, a fine three-dimensional weave in something clear that was not glass. Every filament caught the gantry lamp and handed it to the next one, so the whole chamber held a standing shimmer, like frost on a window at one particular angle and no other.

One-to-one. No interface layer. No governor. No eighty milliseconds.

Eighty milliseconds had killed eleven million people in ninety minutes. Eighty milliseconds was the gap between a Kestrel pilot deciding to move and the Kestrel moving, and it was safe, and it was governed, and it was why the Reach had died with its hands in its pockets.

There was no gap in this.

Leon's hands were shaking on the rail. He noted it the way you note a gauge.

"Ninety-two percent," he said, down to Garren, who had not moved.

"What's the eight."

The eight was this. He walked it and he listed it, because listing was the only thing available.

The left shoulder assembly was not on the machine. It sat on its own cradle six metres away, complete, wired, tested by somebody, waiting. Nine hundred and ten kilos. Mating it meant a hoist, four primary pins aligned to within a tenth of a millimetre, thirty-two fasteners taken to two hundred and eighty newton-metres in a crossed sequence, and then finding out whether the port actuator bus would talk to the spine.

Forty armour plates unfitted, stacked and labelled. Mostly left flank and lower leg.

The secondary coolant loop was unrun. Sixty-one metres of line on the port side. The pump was in a box and the pump was the good kind — forty litres a minute against nine bar, which was what you needed to hold delta-T under eleven degrees across the drive shrouds at continuous rating. The manifold it wanted did not exist yet. It would have to be grown.

The funnel control lattice did not exist at all. Six funnels and no nervous system for them: fourteen kilograms of quantum lattice, and the cell produced that at ninety-six grams an hour when it was happy, which no cell ever was, and you scrapped eleven percent of everything you pulled.

And the frame was uncalibrated. All of it. Every filament in that shimmering room had been grown to a specification and had never once been asked to carry a signal from a living animal, because you calibrated a Psycho-Frame against a nervous system, and there had been exactly one nervous system in the galaxy this frame would accept, and it had not been in the room.

Leon stood in the middle of the floor with all of it laid out and started multiplying.

Lattice: four hundred and ten hours of cell time with the cure cycles and the two-hour purge between materials. Coolant: eighty hours of two men bent double in a volume designed for one. Armour: three hundred and twenty fasteners, torque-sequenced, forty hours. Shoulder mate: a day if it went well, nine if it did not. Calibration: unbounded, and the only part that mattered.

Machine time, four thousand one hundred hours. Man-hours, two thousand two hundred.

Two men. Fourteen-hour days.

Minus the picket.

The Dominion survey sweep came through Meridian every thirty-one days and sat in the system for four. In those four days you could not run the cell, because the cell put six hundred kilowatts of waste heat up the ventilation stack into a thin cold atmosphere, and any orbital thermal survey with a functioning budget would find that on the first pass.

Twenty-seven productive days in thirty-one. Times two.

Five months.

Leon stopped walking.

He stood with his hands at his sides while the number went through him and out and came back around the other way.

Five months. Not four. Not eleven.

His father had shipped twelve months of an obsolete stabiliser dosed at thirty-one kilos, and forty crates of ration, and a four-kilowatt heater, and a fabrication cell with thirty-one tonnes of stock behind it. And he had left eight percent of a machine undone.

The eight percent was not what was left over when he ran out of time.

The eight percent was sized.

It was sized for two men with the skills these two men had, working the days this planet allowed, in the time this girl had left.

You did the arithmetic.

Not hoped. Not prayed. Not written a letter. Sat down with a hard problem, solved it, built the answer, shipped it under a grain manifest to a rock nobody wanted, and cut a slot in it exactly the shape of his son.

Leon discovered that he was furious. Under the fury was something plainer and much worse, which was that he had been counted on by a man he had not held a proper conversation with in six years.

"Leon," Garren said.

He was at the terminal.

It was a squat console on a plinth at the foot of the gantry. It had woken with the lights. One file flagged. Eleven minutes and forty seconds long, recorded — the header said — four years and two months before the invasion.

Leon put his thumb on it.

His father's face came up on the panel and he was younger than Leon remembered him, which was the wrong way round, and he was sitting in a room Leon did not recognise with a coffee at his elbow that he did not touch once in eleven minutes and forty seconds.

"Leon."

Not hello. Not son. The name, entered like a value into a field.

"If you are hearing this, several things are true, and I am going to list them, because you think better with a list and so do I.

"One. I am dead.

"Two. The peace has failed.

"Three. You have the keys, which means the package went out, which means it went out automatically, which means nobody chose to send it and nobody had the opportunity to change their mind. I want you to understand that the absence of a message from me is not itself a message. There simply was not one. I did not know what to write and I did not want to spend the last hour I had writing badly."

He shifted in the chair. Behind him, soft in the depth of field, a whiteboard carried perhaps four hundred lines.

"I built this because the data said the peace would not hold.

"That is the entire reason and I am not going to dress it for you. The year you turned nine I began collating Dominion industrial output against their published civil demand. The gap opened in the third year and never closed. Nobody forges eleven hundred kilotonnes of high-grade structural per annum for silos.

"I took it to the Concord four times. I was told, four times, in four different rooms, by people I liked, that a thousand and six years of peace was itself the evidence, and that a man who looks for a war will find one.

"They were not stupid and they were not corrupt. They had agreed among themselves that the last thousand years were a law of nature rather than a run of luck. There is no experiment that dislodges that. I stopped trying to design one.

"A scientist does not argue with a room. A scientist prepares for what the data shows and lets the room find out on its own schedule.

"So I built you a weapon and I put it in a hole."

Leon's jaw had set at some point. He made it let go.

"Now the warning. Sit down for this part. I know you and you are standing.

"The Psycho-Frame is one-to-one. There is no interface layer. There is no arbitration. The civilian Halo Link is safe because it is slow — it reads intent, checks it against a governor, and executes eighty milliseconds later, and in those eighty milliseconds the governor removes anything that would injure you.

"I have removed the governor. There is nothing between you and it. Nothing.

"The coupling is bidirectional and unbuffered, and you must understand what bidirectional means here. It does not only read. Under load it writes. Above your sync figure the frame stops taking dictation and begins to impose its own state on your nervous system, and your nervous system, being made of meat, will comply, because meat complies.

"The failure mode is not that you lose control of the machine. The failure mode is that you lose control of your body while the machine continues to fly perfectly.

"Your figure is in the package. Do not exceed it. Do not test it. Do not tell yourself that a curve computed on a hundred and forty subjects has an error bar you can live inside. It has one. It is not for you.

"Second. The Zero System.

"It is a probability engine running on a local VEDA terminal. It is not prophecy and it does not see the future. It computes branch outcomes from present state faster than a cortex can produce them, and then — this is the part that damages people — it renders them. All of them. At once.

"You will hold, as memory, forty or fifty futures that have not occurred. Most of them bad. Several of them containing people you love. They will have the full texture of things you have lived, because your brain does not keep a separate drawer for events it has merely been shown.

"Pilots do not break on the branches. Pilots break in the interval between them, standing still, comparing.

"So: pick one. Commit. Do not audit it. The frame will execute a decision that is worse than the best available decision with complete loyalty, and it will punish a correct decision made hesitantly, because a Psycho-Frame has no representation for doubt except as a control input.

"Doubt as a control input is a tremor. At forty-eight tonnes, a tremor is a structural event.

"Conviction is not a virtue in this cockpit. It is a load-bearing member."

He looked off the pickup then, for the first time, and came back.

"Third.

"I was not there for most of it. I know. I have gone back through the calendars and I can give you the exact number of days I was absent in each of the last nine years, and I am not going to say the number, because you would keep it, and there is no use in you having it.

"I would rather be accurate than comforting, so. I did not miss those years because the work mattered more than you did. I missed them because the work was the only room in that house where I was any use, and I went to the room where I was any use, every day, for twenty years. By the time I understood that this was a choice and not a circumstance I had already made it about six thousand times and it had stopped being reversible.

"You will hear that as an excuse. It is not. An excuse is offered in the expectation of relief. I am not expecting any.

"You are competent at the part I was bad at. Your mother's doing and not mine. I have watched you make your sister laugh on days when I could not make her eat, and I have stood in a doorway with nothing to add, and gone back down to the lab, and been glad the two of you had the room to yourselves.

"That is what I was, Leon. That is the whole of it. There is no second half."

Say it, Leon thought. Four letters. Say the word.

He did not say the word.

"Fourth. This is not advice. It is an instruction, and it is the only one in this recording.

"There is a file in this vault designated OMEGA-7. I am not going to tell you what is in it. I am not going to characterise it, or give you its size, or tell you the field it belongs to, because I know precisely how much of it you can reconstruct from any of those.

"Do not open it.

"Now. I have known you for twenty-one years and I have never once seen you leave a closed thing closed. You will open it. You will hold out longer than I would have, and then you will open it, because you are my son and this is the material we are made of. I am not going to insult either of us by pretending otherwise.

"So the instruction is actually this.

"When you open it — do not tell your sister. Not any part of it. Not a summary. Not a sanitised version. Not the shape of it. She is quicker than either of us and she will take a corner of it and have the rest inside a week.

"I am aware of what I am asking. I am asking you to carry it instead. That is not fair and it is not kind and it is the correct allocation of load.

"And keep her away from the frame. Not out of the hangar. Away from it. She does not touch it and she is not inside the volume when it is powered.

"One more thing about your sister and then I am finished. If she is ever inside that volume under power, the frame will not misbehave. It will run beautifully.

"Understand that this is the bad case.

"This is not superstition and it is not a father being careful with a sick child. It is a measurement."

He reached forward.

"That's all. The cell is calibrated. The stock is good. The left shoulder wants a nine-millimetre shim on the upper pin. It always did. I never fixed it.

"Do the work."

The panel went dark.

The vault made the small ticking noise a cold room makes.

"He said my name wrong."

She was eleven metres behind them, at the edge of the lamp fall, standing very straight the way she stood when standing was costing her.

Leon's body did several unhelpful things at once. She had come down. Sixty-one metres, alone, in the dark, on a platform rated for crates, with an oxygen bottle on a strap over one shoulder and Pip riding at her collarbone with its lights dimmed almost out so as not to be a bright thing in a dark room.

"How long have you—"

"All of it." She started walking. Slowly. Heel first, weight straight down through the leg, the way Orr had taught her, the way that cost the least. Nine metres. Seven. "From if you are hearing this."

"El—"

"He said my name wrong," she said again. "Eliana. Flat. Like a part number. He said your sister four times and my name once, and the once was a label on a jar."

She stopped.

Not at the machine. Leon realised she had not looked at the machine. She had ridden a hoist sixty-one metres down a rock shaft into a room with a twenty-metre war frame standing in it, and she had not once raised her eyes above the height of a man.

"There's a heater in that crate," she said. "A good one. Industrial. Rations for two years. A water plant. A room in the corner with the air already set."

"Yes."

"He set the air for me."

"He did."

"Thirty percent." Her mouth moved. It was not a smile. "He got the number right."

"El."

"He got the number right and he never, at any point, intended for me to be in the room." Her voice did not rise. It went flatter, which was worse. "He built me a house on a dead planet as a contingency, and then he told you to keep me out of the hangar, and then he died. Every one of those was a decision made about my life in a room I wasn't in."

Pip's fans went up half a note. She lifted her hand without looking and it dropped into her palm and shut off.

"You do it too," she said.

"That's not—"

"You do it constantly. You did it for fourteen months at Ninepenny. One day you'll tell me what happened in the ninth month, and until then you'll go on deciding, on my behalf, in a room I'm not in, how much of my own life I'm allowed to be told about."

Leon's mouth was dry. He had a joke somewhere. He looked for it and it was not where he kept them.

"That's what the men in this family do," she said. "You decide what I can survive hearing. Not one of you has ever been right about it. Not one of you has ever asked."

Then she looked at Unit-02.

All of it, feet to sensor band, chin coming up and up. Her face did not change.

"It's very big," she said.

"Yes."

"I'm not frightened of it." She said it the way you correct an entry on a form. "You were about to check."

He had been.

She turned back toward the hoist. Then stopped, because turning had cost her, and took two breaths off the bottle with her eyes shut. Leon stood with his hands open at his sides and did not go to her, because going to her where anyone could see was not permitted and never had been.

"You know what I want out of this," she said, over her shoulder. "The vault, the machine, the five months. Whatever you're going to turn into down here."

"Tell me."

"Clothes that fit." Dead level. "That was the deal. When I own real clothes — a coat that's mine, in my size, bought new — you all consider treating me like an adult. That was the joke when I was fifteen."

She began to walk.

"It isn't a joke any more, Leon. It's just the terms."

Eleven metres to the platform. She took them one at a time, and he counted them, and there was nothing he could do with the number.

He did not look at the crate with the fan assembly on top of it. He had a great deal of practice now at not looking at things.

Garren had not moved through any of it.

He stood where he had been standing since the tarpaulin came down, both hands in his jacket pockets, head back, reading the chest glacis with the flat attention of a man checking a serial plate against a work order.

Leon waited.

"Eleven years," Garren said. "Under him."

"I know."

Garren coughed. Once. Wiped his mouth with the back of his wrist.

"I signed the manifest."

He turned and walked to the hoist.

Leon stayed.

He said he wanted an hour with the cell diagnostics, and that was true in the sense that he opened the cell diagnostics. They ran for nineteen minutes and came back clean and he read a hundred and forty lines of green and retained none of them.

The hoist went up. The clamps let go, and then the long diminishing whine, and then nothing, and the vault settled back into its own sound — lamp ballasts humming at four hundred hertz, and the very slow tick of metal that had been at minus nine for twenty-two years and was now at minus six.

He went back to the terminal.

The directory was there. His father had not hidden it. That was the thing that kept turning over: not hidden, not passworded, not buried under a false name in a stack of survey returns. It sat in the root, third from the bottom, in among the archives.

Three hundred and eleven gigabytes. Large for a document. Small for a dataset.

He looked at the file size for some time, because the file size was information, and he had not been told not to look at the file size.

OMEGA-7.

He sat down on the plinth step. The cold came up through his trousers immediately.

He took his gloves off and put them on his knee and blew on his hands, which did nothing, because the air and the hands were the same temperature.

Do not open it.

One instruction. Six years. The man had been dead fourteen months and had built him a weapon and had counted the days it would take him to finish it and had been right about all of it, including the shim.

Leon put his hands flat on his thighs.

He thought about a coat in a crate, girl's twelve, tag on. About a paediatric dosing column that was still correct. About a habitat programme with two profiles in it, only one of them named.

He thought: he provisioned this place for her and then told me to keep her out of the hangar.

He thought: he wrote an instruction he knew I'd break, and then he wrote the instruction that comes after I break it. Which makes the second one the real one. Which means he wasn't protecting the file.

He was staging the sequence.

That was a thought he could not give back.

He stood up. He walked away from the terminal, properly away, twenty metres, out onto the open floor under the machine, where the shoulder cradle sat with nine hundred and ten kilos on it waiting for a shim that had never been made.

He found stock on the third rack. Grade five, two millimetres over. He measured the pin bore twice, cut, filed the burr, checked it with the gauge and then checked it again with the gauge turned the other way.

Thirty-one minutes. It was good work and it did not need doing tonight.

He set it on the cradle rail where he would find it in the morning.

Then he stood in the middle of the vault with his hands hanging and the frost crust breaking under his boots and the ballasts humming, and he did not go up the ladder, and he did not go to bed, and he was aware of the terminal behind him the entire time with the particular awareness of a man who knows exactly how many steps a thing is.

Eleven. It was eleven steps.

He got to four hours.

The vault ran cold at night because Leon had told it to.

Habitat draw was 4.1 kilowatts on the daylight cycle and 2.6 after. The difference was eleven extra days of feedstock at the far end of the schedule, so at twenty-two hundred the recyclers stepped down to a third, the atmosphere pumps went to intermittent, and the deck plates began giving their heat back into the basalt. By midnight the terminal bay had lost two and a half degrees. By three it had lost four. The rock took everything eventually. The rock was two hundred and eleven kelvin and patient.

He worked in the cold. It kept the console off its thermal limiter, and it kept him honest.

The terminal had been sitting with the file index open for eight days, cursor parked one line above OMEGA-7, and for eight days he had walked around it the way you walk around a hole in a floor you have decided is structural.

He had done work — that was what he would have said, and it would have been true. In eight days he had closed out the left shoulder actuator housing, all six sintering passes, and pulled the fabrication cell's positional error from forty-one microns to nine by rebuilding the feedstock hopper agitator out of a survey-crew fan bearing that had been sitting in a drawer since before he was born. He had run the number-two GN drive to eleven percent and held it ninety seconds with his palm flat on the containment shell like a man listening to a horse; shell surface came up to thirty-four degrees and the coolant loop never went above six litres a minute. He had catalogued the funnel racks, all six, and found two with degraded seals. He had slept four hours a night and lied about it to Garren, who did not believe him and did not press. He had spent two evenings learning the Old Astraian word for door and pronouncing it so badly that his sister had put her face in both hands and stayed there. He had run seven low-authority coupling sessions in the Unit-02 cradle — eleven, fourteen, nineteen percent — and come out of every one of them tasting hot coins, and out of the fifth with a left hand that would not close for ninety seconds. And four times, four separate nights, he had read his father's log start to finish looking for a sentence that gave him permission to open the file.

It was not in there. He had checked four times. That was the whole of what those eight days had been.

On the ninth night he sat down, put his hand on the reader plate, and opened it.

The first thing was not horror.

The archive unpacked to 1.94 terabytes and threw a directory tree three levels deep, and the top of it was labelled in his father's flat capitals. CLINICAL. SUBJECT: E.Z. LONGITUDINAL.

Under that, in date order, twenty years of a man trying to save his daughter.

Leon opened the earliest one, because he opened things in order.

ENTRY 0004. CS 1183.115. Subject age 1y 4m. Baseline interferometry of dermal and subdermal lattice complete. Structural degradation confirmed at 0.31% per annum, non-linear. No case in the Concord register with onset under four years. The literature is of no use to me. Beginning again from raw measurement.

ENTRY 0019. CS 1184.008. Candidate compound Halvarin-4 discontinued at day sixty. It suppresses the symptom set for eleven days and then accelerates degradation by a factor of 2.6. I have made her worse. Records preserved in full so that nobody repeats it.

ENTRY 0044. CS 1185.221. Third structural analogue class exhausted. If the failure mode were chemical, one of the ninety-one compounds tested to date would have moved the curve. Not one has moved the curve. I am therefore looking in the wrong discipline. Reassigning.

Leon read for two hours and did not move except to scroll.

There was a chart. It lived in its own file and it had been maintained by hand across two decades, and it was the ugliest object he had ever looked at. Attrition rate on the vertical. Subject age on the horizontal. A scatter of measured points, a fitted line, and the line went up, and it kept going up, and every place it bent his father had put a margin note recording what he had tried that year and what it had cost.

The margin notes were the worst part. They were not despair. They were procurement.

Sample cost 40,000. Sample cost 112,000. Cell line donated, no charge, Dr. K. declined payment.

The points got closer together as the years went on. He was measuring her more often. He was measuring her more often because the number was moving faster.

ENTRY 0212. CS 1189.301. Subject age 7y 2m. Tessamine trial concluded. Formulation stable. Tolerance acceptable. Hepatic load within limits at 40mg/day indefinitely. It does not treat the disease. It does not slow the disease. It reduces pain by an estimated sixty to seventy percent and improves sleep continuity by roughly two hours a night. I have spent four years and eleven months building an analgesic. Synthesis route filed for open manufacture. No patent, no licence, no royalty. Raw cost per week should not exceed two marks anywhere in the Reach.

Leon stopped.

Thirty-one marks a week. Mabry's counter with the wire grille, and the man who chalked the price on a slate every Tuesday so that nobody could argue with him about what it had been the week before. Four marks a shift on the Bellows. Fourteen months of that arithmetic, and it ran now without being asked, the way it always ran: two marks of drug and twenty-nine marks of distance, and a father who had given the formula away for nothing precisely so that this could not happen to her, dead fifteen months and unreachable.

He put his hand over his mouth. He took it away. He kept reading, because that was what was available.

ENTRY 0388. CS 1192.117. Subject age 10y. Sixth immunological approach abandoned. Her immune function is not implicated. It never was. I pursued it for nineteen months because it was the last remaining field in which I had standing, and standing is not a reason.

ENTRY 0501. CS 1194.244. I have written to Halloway, to Serrin, to the Ostmark group, and to two people I do not respect. Serrin replied. He was kind. Kindness is not a result.

Some of the entries were audio. Leon found the first one at the end of the fifth year and played it before he had decided to, and his father's voice came out of an eighty-year-old survey console at fourteen percent volume, flat, unhurried, dictating into what sounded like a room with a hard floor.

"Entry six one one. Series twelve, day nine. Uptake is negligible at every dosage above four milligrams, which I should have predicted from the day-three data and did not. I want it recorded that I did not predict it." A pause. Papers. "I am going to stop for the evening. She has been sitting on the bench behind me for forty minutes and she has stopped asking questions, which means she is bored, and boredom in a seven-year-old is a diagnostic sign of a father who has lost track of the time. End entry."

Leon played it again.

Then he played it a third time, and got up, and stood facing the wall with his arms folded until the console's fan cycled down.

He skipped nothing after that. It was a decision he had made without noticing, somewhere in the second hour: if the man had written it, he would read it, all of it, the failures at full length. The dead ends had dates. Some of the dead ends were three years long.

And in the middle of it, out of format, sitting in the sequence like a stone in a boot:

ENTRY 0176. CS 1188.052. Subject age 6y 1m. Trial series nine terminated at day four. No effect. Sample handling was poor on days two and three. The error is mine.

E. asked me tonight whether I would still be doing this work if she were well. I said no. She said then she was glad she was ill, because otherwise I would have to do something boring instead.

I am recording this because I want to remember that I said no, and that I let her be glad, and that I did not correct her.

Leon got up.

He walked to the far end of the bay and stood facing the rock. It was basalt. It had been cut eighty years ago with a thermal lance and the tool marks were still on it, overlapping arcs about four hundred millimetres across.

He counted them. Thirty-one in his field of view.

He counted them again and got thirty-one.

Then he sat back down.

The intercom clicked. It was a hardwired line, forty-one metres of copper up the shaft, and it popped when it opened because nobody had ever bothered to fix the relay.

"Light's on in the pit," Garren said.

"I'm working."

"You were working at midnight."

"I'm thorough."

The line stayed open. Garren breathed in it — the wet catch on the intake that thirty years of lattice dust had built into him, audible from forty metres up.

"Shoulder cell done?"

"Six passes. Nine microns."

"Mm." A pause of exactly the length Garren used instead of a question. "Your sister's oxygen was reading one point eight this evening. She had it up."

Leon's eyes did not leave the screen. "She'd been on the stairs."

"She had. Eleven minutes and forty. She timed herself." Another pause. "Told me not to tell you."

"You told me."

"I did." The relay popped. "Go to bed at some point."

The line went dead.

Leon sat with his hand on the reader plate for eleven seconds. Then he opened the next directory, and did not go to bed.

The clinical directory ended at CS 1202. Eleven months before the invasion. The last entry in it was four lines long: the ninety-fourth compound class had failed, the therapeutic line was closed permanently, and there was one remaining avenue, which was characterisation.

The characterisation directory was nine times the size of everything above it.

This is what he did instead, Leon thought, and then stopped thinking in sentences and began reading properly — front matter, definitions, method, results, the way you read a specification you intend to build from.

It was the finest piece of physics he had ever seen.

His father had stopped trying to fix her and had started, with the entire attention of a man who had nothing left to spend it on, to describe her. Sub-cellular interferometry at 0.4-nanometre resolution. Lattice-strain tensors sampled at four hundred points across a hand-sized area, forty times a second, eleven days continuous, subject seated, subject supine, subject asleep. Cryogenic isolation runs to strip thermal noise out of the baseline. A shielded chamber cut into bedrock with an ambient magnetic floor under two picotesla, because at that scale the planet itself was loud.

And what he found, and confirmed, and re-confirmed across seven years, was that the tissue was oscillating.

Not vibrating. Not jittering thermally. Oscillating: a standing wave, phase-locked across her entire body, coherent cell to cell and limb to limb, fundamental at 1.9427 kilohertz, coherence quality factor above ten to the sixth. The whole structure ringing in step. A struck bell that never stopped being struck.

Leon read the quality factor twice and understood it the way an engineer understands a load limit.

Matter does not hold at that frequency. Not organic matter, not at macroscopic scale, not coherently. Every interatomic bond in her carried an oscillation superimposed on it that never damped and never dephased, and the energy had to go somewhere, and it went into bond fatigue. Distributed. Uniform. Everywhere at once, awake and asleep, since before she could walk.

Verrine decay was not an illness. It was a resonance failure of the material.

She is shaking herself apart. Not a figure of speech. A fatigue calculation, and his father had run it to nine places.

The waveform was filed complete. Full spectral description, harmonic content to the eleventh order, phase relationships, thermal and postural dependencies, the measurable effect of exertion, the measurable effect of fear. Two decades of a living woman rendered as an equation — exact, elegant, and of no use whatsoever in saving her.

He had given it a designation, the way you do.

HARMONIC E.

Leon noted, in the flat internal register he used for documentation, that nowhere in nine hundred gigabytes had his father written down what the E stood for. Not in the front matter. Not in the nomenclature table, where every other symbol was defined to three decimals of pedantry. It was the only undefined term in the corpus.

Sloppy, he thought.

Then: No.

Then he knew.

It took about a second, and the second was not spent working it out. It was spent on the small administrative act of accepting that he had.

Eliana.

Twenty years of writing his daughter down, and he had not been able to make himself type her name at the head of it, so he had used the letter, and had left the letter undefined so that he would never once have to see the definition rendered on a screen.

The recyclers cycled. The cold came up through the deck into his boots.

He was a coward about one letter, Leon thought. He was not a coward about anything else.

He kept reading.

It was in the appendices. The good material always is.

Appendix C was a plot. Amplitude against frequency, log-log. The fundamental at 1.9427 kilohertz and the harmonic stack marching off to the right in that particular lopsided pattern — third order suppressed, fifth over-strong, seventh doing the strange little double-peaked thing his father had spent an entire subsection failing to explain and then, in one dry closing line, declining to explain further.

Leon looked at it for about four seconds.

Then his hands went cold, and it was not a feeling, it was peripheral vasoconstriction, and he noticed it the way he noticed a pressure drop.

He had seen that curve before. Eight days ago. Six days ago. Yesterday afternoon, on a hardcopy taped to the cradle frame at eye height because he kept needing it and did not trust the console not to sleep.

It was the Psycho-Frame core tuning curve.

It was the first figure in OMEGA-PF/CORE/TUNE-00, the document that defined what the coupling lattice was cut to — the resonance envelope the entire frame was fabricated around, nine hundred and forty thousand lattice cells all seeded to one reference so that a human nervous system could be carried at one to one with no interface delay. He had read TUNE-00 eleven times in eight days. He had built two shoulder cells to it. He knew the shape of that seventh-order split the way he knew his own signature.

The tuning target in that document was labelled, throughout, E-ref.

He had assumed it stood for eigenmode.

"No," he said. Out loud. In an empty room, forty metres under a dead world.

There were reasons for it to be coincidence and he listed them at speed, because that is what you do. Resonance curves in engineered lattices cluster; there are only so many stable configurations in that band. The double peak could be an instrumentation artefact — two devices with similar anti-aliasing produce similar liars. Coherent kilohertz structures are a small family and members of a small family look alike. All of it true. All of it the kind of true a competent man says to himself in the four seconds before he does the work.

Then he did the work.

He checked it three ways.

First, the plots. He pulled the Appendix C raw trace and the TUNE-00 reference into the same axes, normalised amplitude, and differenced them point by point. Four thousand and ninety-six points. The console had no vector unit and took forty seconds over it, fan up, case temperature at fifty-one.

The residual came back flat with noise on it. Peak deviation across the entire spectrum: 0.0004 percent. That was the instrument floor. Two curves do not agree to the instrument floor because they are similar. They agree to the instrument floor because they are the same measurement.

He refused it. He said, aloud, that both traces might have been resampled by the same tooling, and a shared windowing function will manufacture agreement out of nothing, and that was a real objection, and he was pleased with himself for about eleven seconds for having made it.

So, second: he went behind the plots to the raw interferometry. Unprocessed. Eleven days of it, four hundred points at forty hertz, taken off his sister's left forearm when she was nineteen years old and had sat still for it. He wrote his own transform. He did not use his father's tooling. He did not use his father's window. He binned it cold, by hand, and set it running, and the console took six minutes and eleven seconds and pushed its case to sixty-one degrees and throttled twice.

Fundamental: 1.94271 kilohertz. Harmonic stack coming up out of the noise floor in exactly the lopsided shape taped to the cradle frame. Third suppressed. Fifth strong. Seventh split.

Third, because two is not three, he stopped reading documents and went to the machine.

The fabrication cell in the next chamber ran off a lattice controller with its seed values burned into non-volatile store — the literal numbers the sintering head used to lay down a single coupling cell. Hard-coded eleven years ago by his father's own hand, checksummed, never revised, and never intended to be read by a person again. Leon put a probe on the maintenance header and dumped the block raw, and read it as hexadecimal, and converted it himself on paper because he did not want a tool between himself and the answer.

The primary seed was 1.9427104.

Nine significant figures. It matched the raw sample data to the last one.

Leon sat back.

The frame was not tuned to a resonance that resembled his sister's.

The frame was tuned to his sister.

He assembled it in order. Each item was worse than the one before it. He did not stop, because stopping was not something his mind offered him.

One.

Twenty years of failing to cure her had produced the most complete description of a coherent living macro-scale resonance in the history of physics. There was no other document like it anywhere, and there never had been, because nothing that oscillates like that lives long enough to be studied properly. And later — years later — when Aria Zadkiel sat down to build a coupling lattice that could carry a human nervous system with zero interface lag, the thing the Reach had failed to build in a thousand years, the thing eighty milliseconds of civilian Halo Link had cost eleven million people, he needed exactly one input.

A rigorous mathematical description of a living structure that resonates coherently.

He had one. He had the only one. He had written it on his daughter, one measurement at a time, across two decades, while telling her it was work.

The System-Omega Psycho-Frame was made out of a father's failure to save his child. Both units. Unit-01 too. Unit-01, which had unmade eight hundred and seventy warships over the Reach and then unmade the man inside it in fifty-one minutes.

Two.

And that was why.

Leon had spent fourteen months believing what everybody believed — that his father had died of neural feedback because the machine was too much for a human being. It was the kind of sentence people say at a distance, and it had let him keep the death vague, and he had wanted it vague.

Now he had the tuning curve in front of him and he understood the failure mode exactly.

The frame does not amplify a pilot. The frame rings. It has one note. It holds that note, and coupling into it means putting your nervous system into phase competition with a resonance that will not move for you and cannot be persuaded. Every pilot who ever lay in that cradle was fighting the frame. Not commanding it. Fighting it, continuously, for the whole duration of contact, and losing at a rate proportional to how far off the note they sat.

Nobody matches it. There is nothing alive that matches it. That is the design problem, and his father had known it before he ever strapped in, and had strapped in.

Three.

The sync curve.

Maximum safe neural coupling. The number Leon had carried in his mouth for fourteen months like a coin he could neither swallow nor spit: 91.7. His father's 61.4. Unit-02 wanting roughly 85 for full authority. Six points of headroom he had never told anybody about, not Garren, not Eliana, not once.

He had always been told it was a talent rating. Reflex quality. Spatial intuition. The thing he did at the Academy where he could call a three-body intercept before the plot resolved and could not explain how he had done it, and one instructor wrote gifted on his file and another wrote unnerving and both of them were describing the same measurement. Fifteen years of people telling him he had his mother's hands and his father's head.

It is not a talent rating. Appendix F is a table. Deviation from Harmonic E — phase and spectral — against predicted coupling ceiling. Monotone. Single-input.

Proximity. How close your own lattice sits to hers.

His father scored 61.4 because he was her father and carried half of her.

Leon scored 91.7 because he is her brother.

He made himself sit with it. Everything. The reflexes. The arithmetic that ran whether or not he asked for it. The way he had beaten an eighty-millisecond lag his entire life without knowing there was a lag to beat, the way a man born at altitude does not know that he is strong. The whole specification of Leon Zadkiel, the thing he had been praised for since he was nine — a partial, diluted, non-lethal expression of the anomaly that was, at that moment, forty-one metres above his head, asleep, twenty-eight point two kilograms, eleven minutes and forty seconds to a flight of stairs.

She got the disease. He got the gift. Same waveform. Different amplitude.

I have been living off her. He corrected it, because it was self-pity and also imprecise. No. We were handed the same thing. Hers came at full power.

The correction did not do anything.

Four.

And then he understood the dead-man package, and he put both hands flat on the desk.

No message. No words at all. Fourteen months of turning it over — three files, the keys to Unit-02, the coordinates of Meridian-7, and the complete sync-curve dataset, and not one syllable from a father to his children. Leon had been angry about it in a low, permanent, load-bearing way for over a year. He had assumed it was time. He had assumed the man had been climbing into the cradle with forty seconds and a checklist.

It was not time.

His father had sent the number because he could not type the sentence. He could not write Leon, your sister is the reason you are what you are. He could not write the machine I am about to fly is made out of her. So he sent the mathematics and let his son do the derivation himself, in his own time, from first principles — a man who had refused to define one letter for twenty years choosing, at the end, to transmit a figure instead of a fact.

Leon had done the derivation.

He had done it in a two-berth pod on a randomised vector eleven days out from a burning world, cabin lights at four percent, his sister asleep on his chest with her hand shut in his collar. He had looked at 91.7 and been frightened of it and proud of it at the same time and had not known what he was looking at.

He had read his father's confession and thought it was a score.

There was one more section.

Eleven pages. The last thing written in the entire corpus, dated CS 1203.019, six weeks before the Dominion executed the Concord envoy on a live feed. Titled without ornament.

CARRIER.

Leon read the first paragraph and understood that his father had asked the obvious question. He had never in his life been able to not ask the obvious question. Neither had his son.

If a pilot's coupling ceiling is set by proximity to Harmonic E, what is the ceiling for Harmonic E itself?

The answer was on the second page and it was not a number.

She has no sync figure. She cannot have one. A sync figure describes how well a pilot approximates the reference, and she does not approximate the reference. She is the reference. Couple her and there is no phase competition, because there is nothing to compete with. No governor. No ceiling. The safety limit that has existed for every human being who ever touched a Psycho-Frame is an artefact of mismatch, and she has no mismatch.

Output would not be bounded by the pilot. Output would be bounded by what the drives could physically make, and by nothing else in the universe.

Then the third page. The mechanism.

The frame holds its field by drawing structural coherence out of the coupled source. That is how it works. That has always been how it works, and it is in TUNE-00 on page nine, in a single sentence Leon had read eleven times and filed as an abstraction about signal integrity. For a normal pilot the draw is negligible — a rounding error against the mismatch losses, which is why in a thousand years nobody had ever seen it.

Couple a perfect carrier and the draw stops being negligible. The frame takes coherence out of her lattice and puts it into the field. Her lattice is the only thing holding her together. Her lattice is already failing.

The machine eats her. That is not a side effect. That is the power source.

There was a chart.

Of course there was a chart. Attrition rate against percentage of design authority. Below sixty percent it ran flat and unremarkable, no worse than the ordinary business of being alive. Above sixty percent it went vertical, because above sixty percent the effect compounds: coherence loss reduces lattice integrity, reduced integrity increases the draw required to hold the same field, increased draw increases coherence loss. A positive feedback loop with a measured time constant, fitted from her own twenty-year dataset.

Doubling every forty-two seconds of sustained output above sixty percent authority.

And then the integrated figure, flagged in a notation his father had used nowhere else in nine hundred gigabytes, which was simply bold.

TOTAL SURVIVABLE EXPOSURE, CUMULATIVE OVER SUBJECT LIFETIME: 18 min 44 s.

Not per sortie. Cumulative. Total, ever, spend it how you like — a hundred and twelve seconds here, four minutes there, and when it reached zero it reached zero. No reserve behind it. No mechanism by which any of it came back.

Leon read it four times. On the fourth pass he read the units specifically, to be certain they were minutes.

They were minutes.

Under the chart, on its own line, in a document that contained no other line like it, his father had written:

She must never find out that she is useful.

Nothing after it. No recommendation. No contingency. No note on handling. Eleven pages of the cleanest physics in the Reach, then that, then white space, then the end of the file.

Leon looked at the sentence.

His father had not written she must never be used. He had spent his last line on the only variable he could not compute, and he had named it correctly, and the variable was his daughter.

She would say yes. In about four seconds, and then she would argue him flat about it, faster and meaner than anyone expects, and she would be pleased. Twenty-two years of being the reason a room went quiet. Of being carried and dosed and apologised to and costed. Four marks a shift, thirty-one a week, one Academy ring. And then a machine that made her the most consequential object in the galaxy for eighteen minutes and forty-four seconds.

She had worked out the Household Requisition in a day. She had explained it to him in a kitchen, calmly, eating nothing.

Give her this and Vantalar would not need to hunt her at all.

His father had understood his daughter completely, and had loved her exactly, and had recorded her the way he recorded everything. As a design constraint.

Leon did not break.

He noticed that he did not, distantly, and filed it for inspection later. No shaking. He put two fingers on his own carotid and counted against the console clock the way he would check a bearing temperature. Sixty-eight. Two minutes later, sixty-one.

Then he went to work.

He generated a key pair off his own biometric and wrapped OMEGA-7 in it — full corpus, clinical and characterisation and CARRIER together, one sealed volume, one holder. He set the failure behaviour to deny and do not report, so that an attempt to open it would not announce that there was anything there to open. He verified the wrap. He verified it a second time. He re-derived the key fingerprint by hand, on paper, because this was the point at which an error would be permanent.

Then he went into the vault's access ledger.

It was a rolling hash chain. Good practice, standard in Concord installations for sixty years, and it meant he could not simply delete his entries, because a gap in a hash chain is louder than the entry it removes. So he did it properly. He took the nine days of records, stripped the four OMEGA-7 accesses and the six-minute transform job, regenerated the intervening hashes from the surviving entries, and re-signed the chain with the maintenance key that lived in the fabrication cell controller, because eighty-year-old survey installations trusted their own tools without asking them for identification.

Twenty-six minutes. It verified clean on the first pass and he ran it twice more anyway.

As far as the vault was concerned, on the ninth night Leon Zadkiel had run a lattice-cell simulation, walked the shoulder-actuator tolerances one more time, and gone to bed.

He was aware, throughout, of what he was doing.

That was the part the room would not let him have. He was standing in his father's vault, at his father's terminal, holding his father's worst decision, and he was making it again. The same decision, in the same chamber, for the same reason, and the reason was good. It had been good when his father made it. That was precisely what made it the same. He was not weak, and he was not panicking, and he was not confused. He was a competent man doing a careful, deliberate, technically excellent job of ensuring that his sister would never be told what her own body was.

Eleven days before the invasion he had watched a point of light move fifteen seconds of arc in four minutes, done the mathematics correctly, reached the wrong conclusion, and gone inside.

Tonight the mathematics was right and the conclusion was right.

He did it anyway.

He powered the console down and waited for the store to spin off. He picked up his jacket. He climbed the shaft.

Forty-one metres of service ladder at 0.71 g, and he took it in about ninety seconds, because he did not want to be in the shaft.

The habitat ran enriched, twenty-eight percent, and the air changed at the hatch the way it always did — thicker, warmer, faintly like solder. Outside the module the surface pressure was 0.4 bar and the night had eleven hours left in it and the picket's next sweep window opened in six days. None of that had changed in the last five hours. It was strange that none of it had.

Eliana was awake.

She was sitting up with the blanket over her legs and the white cardigan on over her nightshirt, sleeves down past her hands, the hole in the left elbow showing a triangle of pale skin. Cannula hooked over one ear, flow at the low setting, 1.5 litres. Pip sat on the shelf above her with its fans stopped and its indicators dimmed nearly out, which it did at night so as not to be a bright thing in a dark room. Its cells were at seventy-one percent of rated capacity and its hover endurance was down to twenty-six minutes and it had not been told about either.

She had their mother's signet on her thumb, turned so the sunburst sat on the back of her hand. She was moving it around with her forefinger, slowly, which she did when she had been awake a long time.

"You're late," she said.

"You're up."

"I'm always up. It's the great tragedy of my life that there are never any witnesses." Her eyes came round. Pale violet in the low light, which meant she was neither angry nor frightened. Which meant she was simply awake. "Also I'm cold. Which I raise only for the record."

"Noted for the record."

"Because when I have a coat that fits," she said, "I think we can reopen the question of whether I get treated as an adult in this house."

It had years on it now. She said it the way people say old things — fast, sideways, with one corner of her mouth — and it went in under his ribs and stayed.

"When you have a coat that fits," Leon said, "I'll take instruction."

"You'll take instruction now." She pulled the cardigan closed across her chest with both fists. "What were you doing down there? It's nearly four."

He stood in the doorway with all of it in him. 1.9427104. Eighteen forty-four. A letter his father would not define, and one flat line of text he was going to carry for the rest of his life.

"Reading Dad's notes," he said.

It was true. Every word of it was true.

She did not answer straight away.

She looked at him. Not sharply — she never did it sharply. She just looked, thumb still on the signet, holding his face for one beat, and then another, and then a third. One beat longer than the question had been worth. Long enough that he became aware of the recyclers, and of his own hands.

Then she said, "Alright," and lay down, and turned to face the wall.

The hangar was two hundred and ten metres of hollowed basalt with a ceiling somebody had begun to shape eighty years ago and then stopped shaping, and at the far end of it Unit-02 knelt under sixty years of dust and a tarpaulin that had gone to crumbs in their hands.

It took nine days to get it standing.

Not the frame's fault. The frame had been crated under dry nitrogen at a tenth of an atmosphere and had not aged an hour. The gantry was the problem. The survey installation had been built to hoist core samplers and was rated at forty tonnes, and Unit-02 dry — no coolant charge, no battery, no pilot — massed one hundred and sixteen. So they cut the gantry apart and welded it up in a different shape with a spreader beam and four load cells, and Garren ran the numbers twice, because Leon had run them once, in his head, correctly, and Garren did not trust anybody who would not show working.

On the ninth day the frame came up off the cradle at a rate of nine centimetres a second, put one foot down and then the other, and stood on the hangar floor with its head bowed under the rock. The standby lattice woke along the spine in a slow travelling green, segment by segment, forty-one segments, about a second and a half apart.

Eliana was on a crate forty metres back with a blanket over her knees, the enrichment line looped behind one ear, Pip parked on her shoulder.

"It's taller than the house," she said.

"It's taller than three of the house."

"Don't be exact at me."

"Twenty metres. The house was six and a half with the roof. So three point oh eight."

"You did that on purpose."

"I did," Leon said. "It's the only thing I'm good at and I'd like it noticed."

She threw the corner of the blanket at him. It went about a metre and a half, which was everything she had, and she watched it land like it had personally disappointed her.

DAY 14. FIRST SEATING.

He had been inside a Halo Link nine hundred and some times. Academy trainers, rescue frames, the harbour tugs at Halcyon on summer contracts. He knew what a cortical interface was. It was a very obedient stranger standing eighty milliseconds behind you at all times. You learned to throw your intent out ahead of your body and let the stranger catch up, and every pilot in the Reach had learned it so young they stopped noticing it, the way you stop noticing that your own eye has a hole in the middle of it.

The Psycho-Frame was not that.

The seat closed on his ribs at four kilopascals and Garren's voice came flat through the pad in his ear. "Coupling to five. Say the number back to me when I say it, not before."

"Five," Leon said, when Garren said it.

The lattice came up.

There was no arrival. That was the thing he never managed to describe to anyone afterward, including his sister, including himself. With a Halo Link you felt the machine turn up. There was a handshake, a bloom of secondhand proprioception assembling limb by limb, a man putting on a coat in the dark.

The frame did not turn up. It had always been there.

Two hundred and eleven degrees of freedom, and he had always had them. Left knee actuator at nine degrees of flex, forty-one Celsius, and it was his knee and had been his knee since he was a child. Six fin funnels racked dormant in the dorsal cradle, and he felt the mass of each one the way you feel a ring you have worn for years. A right hand with fourteen tonnes of grip authority. His hand. There was no seam anywhere he could get a thumbnail into and lift.

At five percent it was beautiful.

"Six."

At eight he understood that the machine reported its own weather continuously, everywhere, all at once — that this was the same service his skin performed about a cold room, and that he had never once had to think about his skin.

"Ten."

At ten his vision doubled sideways. Not blurred. Doubled, cleanly, two sharp images offset by four degrees, one from the optical cluster in the head and one from his own eyes, and neither of them intended to yield.

"Eleven."

The floor in front of the machine was mapped to eleven centimetres of resolution out to four hundred metres and he could feel the map the way a tongue feels the inside of a mouth.

"Twelve."

Something leaned on him.

Not pain. He was careful about that afterward, because pain would have been simpler. It was a pressure with a shape, and the shape had a rate, and the rate was fast, and every part of him that was made of matter was being asked — politely, continuously — to agree with it.

Four seconds.

He came back on the deck plating with his cheek on cold steel and Garren's knee in his back. The blood out of his nose had made a puddle about the size of a hand, which meant time had passed, which meant nobody had told him how much.

"Six minutes," Garren said, before he asked. "Stay down."

"I'm fine."

"You're not, and I've got the board. Heart went to two-twenty and held there forty seconds after you were out. That isn't a faint. That's the machine still holding you."

Both ears rang. Leon lay on the plating and found the pitch, and it took him about two seconds, which was slower than he liked.

"E," he said.

"What?"

"The ringing. E, four octaves up. Call it twenty-six hundred hertz." He got an elbow under himself. "Cochlear. It's a normal pressure artefact."

"Uh huh."

"It is normal."

"Didn't say a word," said Garren.

Leon washed the liner out under the coolant tap in cold water and put it back on wet, because Eliana came down at eighteen hundred and it was seventeen-forty.

"Twelve percent for four seconds put you on the floor," Garren said behind him. "Unit-02 wants eighty-five for full authority. Say that number so I know it went in."

"Eighty-five."

"And tomorrow?"

"Thirteen," Leon said.

Garren stood there a while with a rag in his hand and thirty years of lattice dust in his lungs. Then he said, "Right," and went to shut down the board.

DAY 19.

Coolant lines ticking as they contracted. The frame cold. Garren at the telemetry board with the trace from the fifteen-percent run still up, running it back at quarter speed for the fourth time.

"Your problem," he said, "is that you think the ceiling is a wall."

"It's a number."

"It's the number where the frame starts writing on you instead of reading you. That's not a wall. That's a waterline." He knocked the board twice with a knuckle. "Above your figure it doesn't stop working. That's what's dangerous about it. It works better. Your father's figure was sixty-one point four. He flew Unit-01 at something north of ninety for fifty-two minutes and took eight hundred and seventy hulls off the board, and every trace I have ever read says he was flying beautifully at minute fifty-one."

"That's meant to frighten me."

"It's meant to inform you," Garren said. "Frightening people is for when they haven't decided. Go and eat."

DAY 21. WEEK 2. LOCOMOTION.

Forty percent. Eleven seconds.

He got it to walk.

It walked like a very large drunk: a nine-metre stride that landed wrong, a compensating stagger, the left foot ploughing two metres of furrow through the regolith outside the north doors, and then a recovery that was mostly a controlled fall into the next step. One hundred and thirty-eight tonnes combat-loaded. The ground shook hard enough that Pip lost attitude at fifty metres and had to sit down on a rock and think about it.

He shut down at eleven seconds because the coupling alarm was no longer a sound. It was a brightness behind the sternum. He had decided, privately, that he would always stop the first time he felt it and never the second.

"How was it?" Eliana said from the vault mouth.

"Embarrassing."

"It walked."

"A man walks. That loitered downhill." He was breathing hard. "It isn't the machine. The machine is perfect. I'm sending it four hundred corrections a second, none of them necessary, all of them arguing. It's like when you think about swallowing."

"And then you can't swallow."

"That. A hundred and thirty-eight tonnes of that."

"So stop thinking about swallowing."

"Thank you. Genuinely. Where were you nine days ago?"

"Sitting down," she said. "As usual. It's very restful, being right."

DAY 39. WEEK 5. FIRST FLIGHT.

Twin GN drives, four minutes eleven from cold, and the frame came off the regolith like something that had been waiting eighty years to stop pretending gravity applied.

Four thousand metres, straight up. Then across at three hundred, over the ash flats north of the observatory, and the whole time he was inside a machine that massed as much as a small terrace of houses and it felt like nothing whatsoever. It felt like being a thought with a body attached.

Sixty-two percent coupling. He had logged forty.

That was the first lie and he told himself it was administrative.

Then the wings.

The overcharged Minovsky drive fed the dorsal emitters and the field came out along two spars, a plane a molecule thick and eleven hundred metres long, and in the thin daylight they were not white. They were something past violet that the optics rendered as white because they had nothing else to offer. They made no sound. There was not enough air to carry any.

He banked left.

The lower wing touched the ground.

He felt it. That was what he could not get over. He felt the crust part along eleven hundred metres of edge with no resistance at all — the field did not slow by any amount the telemetry could resolve — and behind him for eleven kilometres the surface of Meridian-7 opened into a trench four metres wide with walls of glass where the basalt had gone liquid and set again in the time it took him to pass.

He cut the wings, killed the drives, put the frame on its knees on the flats and sat there.

Telemetry: manoeuvre duration nine point four seconds. Heart rate one hundred and ninety-one. Hands on the grips oscillating at approximately six hertz. He watched the trace of that on the board for a while because it was easier than looking out of the canopy.

I did not mean to do that.

Not the trench. He had not meant to touch anything. He had put a wingtip through the crust of a planet the way a man walking a corridor lets his fingers trail along the wall, without deciding to, without noticing, because his body was that size now and he had not learned where the edges of it were.

"Report," Garren said.

"I'm fine. Frame's fine."

"I've got the orbital pass. What is that."

"That's a trench."

"How long."

He ran it. He did not need to run it; the figure was already in him. He ran it because arithmetic was somewhere to stand. "Eleven point two kilometres. Mean width three point nine. Depth variable, call it two point one. About ninety-two thousand cubic metres of basalt."

"And you didn't mean it."

"No."

"Right," said Garren. "Come home."

The trench was there in the morning. It was there in month four. It ran from the flats to the ridge dead straight, and glass takes the light before anything else does, so the first thing you saw at dawn out of the vault mouth was a bright line going off to the horizon.

He looked at it every day.

DAY 63. WEEK 9. ZERO.

The Zero System did not predict. That misconception survived about four seconds.

It enumerated.

He brought it up at low coupling with the frame parked and inert six hundred metres from the observatory, on a still afternoon with nothing happening, and the system took the local state — terrain, atmosphere, his own posture, one survey drone Garren had put up as a stand-in — and gave him the tree.

Every branch. Every branch of every branch. Not the likely ones. All of them, weighted, out to a horizon of eleven seconds, which at combat tempo is a geological era. Thirty-one thousand four hundred and six terminal states in the first frame. He knew the count because the count was one of the things it gave him and he could not not read it.

And each of the thirty-one thousand four hundred and six arrived with the weight of a thing that had happened. That was the part nobody had written down. It was not a diagram. It was remembering thirty-one thousand futures at once, equally, including the four hundred and sixty in which the drone got through and the frame came apart and he felt it come apart, including the eleven in which the frame went into the observatory, including — this was the one — the ones where the vault door was open and his sister was standing in it.

He was sick inside the helmet at about six seconds.

Which is a specific and disgusting problem. A sealed cockpit is a closed volume with a scrubber rated for carbon dioxide and water and nothing else. He had to hold the helmet seal one-handed, blind, run the shutdown by touch through a visor he could not see through, and then sit in it for the four minutes the canopy took to equalise against an outside pressure of 0.41 bar, because you do not crack a cockpit at differential. Then he got out onto the regolith, knelt, and finished being sick where the wind could take it.

Then he sat on the frame's foot for half an hour and worked out what the skill actually was.

It was not seeing more branches. Anyone could see more branches. The local VEDA terminal would hand him a hundred thousand, a million, out to whatever horizon it could carry. Seeing more was the failure mode. Seeing more was how you drowned in a chair.

The skill was pruning.

So he built a discipline, and he built it the way his father would have, which he did not think about at the time.

One. Before engaging Zero, name the objective in a single clause. Not a goal. A clause. Cross that ridge. Kill that emitter. Do not be hit. Anything containing an "and" was two engagements and he would run them consecutively.

Two. Set a cost he refused to pay, in advance, in figures, and let the system delete every branch that spent it. Not don't get hurt. Structural loss above eleven percent. Battery below thirty. Any branch putting the frame within four kilometres of the vault mouth: gone, all of them, whatever they were worth.

Three. Accept the first branch that satisfied the clause and paid under the cost. Not the best branch. The first sufficient one. The best branch was a thing that existed nine hundred milliseconds later, and by then it was not the best branch.

Four, and this took longest, and he never wrote it in the log: do not look at the terminal states. Look at the first move. The system will show you how you die in every world; it has no opinion, it is arithmetic. But a man who reviews eleven thousand versions of his own death every eleven seconds stops being able to do anything at all. So: read the first move, take it, let the tree collapse, read the next first move. Live at the root. Never walk out to the leaves.

By day seventy-one he could hold Zero ninety seconds without a physiological event.

By day seventy-eight the thirty-one thousand had become a texture instead of a list — the way a chord stops being four notes once you have played long enough — and he could feel the tree leaning before he read any of it.

He did not tell Garren that with Zero up the ringing got louder, and that it was still an E.

DAY 91. WEEK 13. THE FUNNELS.

Six heavy GN fin funnels. One point nine metres, three hundred and eighty kilograms each, independently powered, a particle emitter at about a fifth of the frame's main output, a reactionless drive good for twelve g sustained and fourteen in a burst.

Human beings cannot multitask. It is not a training problem. Attention is serial and a switch costs about two hundred milliseconds, and if you are flying seven bodies in a volume forty kilometres across, two hundred milliseconds is a funnel in a cliff.

The first day he tried to fly them.

He lost three into the north ridge inside ninety seconds. Not at once — that would have been one mistake. Three mistakes in series, each of them identical: he took direct control of funnel four to correct an approach, and while he was inside funnel four, two and five went on doing the last thing he had told them, which was run north at twelve g.

Three hundred and eighty kilograms at twelve g into basalt. The micro-repair lattice welds fractures. It does not reassemble a unit that has become eleven thousand pieces across six hundred metres of scree.

They went out with the crawler and picked up what there was. Garren turned over the largest recovered fragment — a section of emitter housing about the size of a dinner plate, still warm — looked at it for a moment, and dropped it in the bin.

"Cell can make you three more," he said. "Nine weeks. It'll eat about a fifth of the feedstock we were holding for the armour skirt."

"I know."

"Want to know what I'd do?"

"Yes."

"Stop flying them."

So Leon stopped flying them.

What he found instead took a fortnight and arrived at about two in the morning while he was thinking about something else, which was where everything came from now. Doctrine.

He did not command the funnels. He briefed them. Each got a written behavioural doctrine the VEDA terminal could execute without him: a station-keeping envelope, a target class, an engagement trigger, a disengagement trigger, a fallback. Funnel one — hold nine hundred metres high-left, fire on any emission source above threshold resolving inside the envelope, break for the frame below twenty-two percent cell. Funnel three — nothing. Silent. Do not emit. Move only to keep line of sight on funnel one. Wait.

Then he took direct control of exactly one, for no more than four seconds, and while he was inside it VEDA held the other five to doctrine.

It was not a trick. It was a different profession. He was not a pilot with six extra hands. He was a man running six subordinates who could not be spoken to once the shooting started, which meant every order had to exist an hour before the enemy did, which meant the whole engagement had to be built in his head in advance and then handed over to five machines that would obey an hour-old idea with total loyalty while the world changed around them. The only live variable was which one he stepped into, and when.

Day one hundred and one. Six funnels, forty kilometres of volume, eleven target drones, four minutes twelve seconds. No losses.

He sat in the cockpit at the end of it and thought, clearly: no pilot in the Reach has ever done that. And then: there is no Reach. And then he ran the shutdown.

DAY 111. THE PICKET.

Three hulls on a thirty-one day cycle. A cutter and two drones running a lazy spiral with a magnetometer and a thermal boom, mapping nothing, looking for nothing, because there was nothing on Meridian-7 and there never had been. A box on a schedule somewhere, ticked.

It shaped everything. Days one to twenty-four: flight, live drives, emission, noise. Days twenty-five to thirty-one: cold frame, fabrication cell at minimum draw, radiators dumping inward into the rock instead of out at the sky. Six days a month of nothing, every month, and Leon spent them in the terminal room with his father's logs and the tremor and the ringing at two thousand six hundred and thirty-seven hertz.

On day one hundred and eleven the picket came eight days early.

Garren caught the drive signature at eleven light-seconds and had ninety seconds to spend. Leon was four kilometres out over the flats at sixty percent with both drives lit.

He got into the north shaft with nine seconds of margin and no room to turn around, which meant going in backwards, which meant walking a hundred and thirty-eight tonnes down a nine-degree slope in reverse by feel with the optics reading nothing but ceiling. Then everything off. Drives cold. Lattice dark. Battery isolated at the bus. The cabin air handler too, because a handler makes heat and heat is a shape on a thermal boom, and four metres of basalt is a great deal of insulation and not an infinite amount.

Nine hours.

He could not open up; venting cabin gas into the shaft would have put a plume up the throat of it. So he sat in three cubic metres of dark with the visor up and a passive lithium hydroxide cartridge doing the only work being done in the machine.

He did arithmetic for two hours. Cabin volume, metabolic load, cartridge capacity, partial pressures, time to symptoms. He had eleven hours before it got interesting and fourteen before it got difficult. He ran it four ways and got four answers inside two percent of each other. Then he was out of arithmetic.

Then he thought about Omega-7.

He had read it on day sixty-eight. Forty minutes to read. Eleven seconds to understand. Fifty-one days to carry.

He could see the attrition curve. He could see everything he had ever read. Compounding above sixty percent of design authority. Doubling every forty-two seconds of sustained output. The integrated projection, cumulative over a lifetime and not per sortie, because his father had been careful about that distinction and had put it in a footnote so that nobody could make a mistake about what kind of budget it was.

Under nineteen minutes.

One line beneath it. Nothing after.

I have run this four times. It does not improve.

Leon sat in the dark inside twenty metres of machine and did not move.

And above the file designation, in the log, in the same hand: Do not open this. When you have opened it, do not tell her. Nineteen months dead and still calling it correctly, both halves, at range. Either love or actuarial confidence. He could not make himself choose.

He thought about two fingers flat on his sternum.

She would use it.

That was where it always came out. Not that she would break. Not that knowing might kill her, though it might. It was that she would look at the figure and do the arithmetic — nearly as fast as he could — and see that nineteen minutes of her bought more than fifty years of almost anybody else, and she would spend it. She had already tried to spend herself on the side of a grain silo.

So I don't tell her.

Nine hours in the dark and he arrived where he had arrived on day sixty-eight, by the same road, which he took as evidence the road was sound, and which was evidence of nothing except that he had walked it enough times to wear a groove in it.

At nine hours and eleven minutes the hardline clicked. "Gone. Two light-minutes and running."

"Copy."

"Say a number."

"Carbon dioxide's eleven thousand parts per million. I've got a headache. I'm fine."

Four seconds of nothing on the line.

"What did you do for nine hours?" Garren said.

"Slept," said Leon.

DAY 119. WEEK 17. SLINGSHOT.

Eleven days left in the cycle. Garren wanted the next one. Leon did not, and it was Leon's machine, which was a sentence neither of them said and which had become true somewhere around week nine.

Six thousand kilometres up, with Meridian-7 hanging underneath like a scab.

The GN-Field Slingshot is not teleportation. It is a compressed field envelope that reduces the effective inertial mass of everything inside it to a small fraction of rest mass, and then dumps the whole photon battery — four point one petajoules, the entire reservoir, in a hundred and eleven milliseconds — into linear acceleration.

He set the run at two million four hundred thousand kilometres. Straight. Into empty sky, with nothing in the volume but vacuum and a bad idea.

Projected terminal: 0.94c.

The acceleration did not feel like acceleration. Inside the envelope his own mass went with it. What it felt like was the universe deciding to leave.

Ahead of him the starfield gathered. That was the only word for it. It slid forward from the sides and packed into a bright ring and the ring shrank and went blue, went violet, went past violet into something the optics rendered white because they had nothing else. Behind him everything went red, then dark, then was simply not there. Forward optics blanked at 0.71c. There was nothing they had been built to do with a sky folded into a cone eleven degrees wide.

Hull temperature. He watched it. Even in vacuum there is a medium — a hundred thousand hydrogen atoms per cubic metre, less than nothing — and at 0.94c they arrive as radiation. Prow armour went from three kelvin to thirteen hundred and seventeen in nine seconds against a laminate rated sixteen hundred continuous. Eighteen percent of margin. Margin is a thing you can spend. The micro-repair lattice reported continuous work across the whole prow, welding as fast as the sky sandblasted it off, and it cost four tenths of a millimetre of coating and eleven kilos of feedstock.

Eight point six seconds at speed.

He came out of the envelope and the deceleration burn was ninety seconds of hard reversal at eleven g through the seat, no envelope, nothing between him and it, and the whole time he was laughing.

That was the part.

He heard it come out of himself. It was not a nice sound and it was not entirely under his control and it went on. Somewhere in the middle of it he understood that he had not laughed since Halcyon. Not in fourteen months of Ninepenny, not at his own jokes, of which he had made hundreds, all of them for her, all of them mounted the way you mount a shelf.

He stopped, and sat still at eleven g with his jaw shut.

Something in there had enjoyed it. Something in there had crossed two and a half million kilometres in nine seconds and come out delighted, and it had not asked him first, and it did not appear to have any position at all on eleven million dead, or on a woman in a stairwell, or on a man named Vale in a cellar with a coat on a hook.

"Say something," Garren said.

"Slingshot works."

"That isn't what I asked."

"Slingshot works," Leon said, and brought it home.

THE BODY.

He kept the log himself. Garren kept another one. They did not compare them and both of them knew it.

Week 6. Tremor, left hand, approximately six hertz, present at rest. Onset the morning after two hundred seconds at fifty-four percent. It did not resolve that day. It did not resolve that week. By week nine he stopped entering it, because the same line every day is not data. He learned to hold a cup right-handed, eat right-handed, keep the left in a pocket, and — this took practice — to set the left flat on a table when he sat down, palm down, fingers spread. A flat hand does not visibly shake.

Week 7. Hearing. He built the test out of a signal generator and a pair of shop cans. Sweeps, five hundred to eight thousand hertz, both ears, thresholds recorded twice on separate days. There was a notch. Left ear, centred at 2,637 hertz, eighteen decibels down, not moving, not returning.

Two thousand six hundred and thirty-seven hertz is E7.

It is the note the ringing had been on day fourteen. Seven weeks of a fixed tone in his skull and it had burned a hole at exactly that frequency, the way a filament burns a spot into a retina.

He wrote 18 dB @ 2637 in the log and wrote nothing else.

Week 8 onward. Nosebleeds. Initially recorded. By week eleven he carried a rag clipped inside the collar of the flight liner as standard kit, the way you carry a spare seal, and had stopped entering them, and had — he noticed this one afternoon with a sort of distant professional interest — stopped noticing them. He found the front of a shirt stiff with old blood in the wash and could not identify the day.

Sleep. Two hours. Sometimes three. Not restful; he came out of them the way you come off a bad connection, mid-sentence, already doing sums. He compensated with the stimulants in the vault medical stores until Garren counted them, and then he compensated by not sleeping, which was about as effective and cost nothing.

Week 12. Words.

That was the one.

He was in the fabrication bay and he wanted the thing you tighten the collar bolts with, the thing with the ratchet, and it was in his hand, and he had used it four hundred times, and the word was gone. Not misplaced. Gone, cleanly, the way a file is gone. He stood holding it for perhaps three seconds and then said, "Pass me the eleven-mil," and Garren passed him the eleven-mil driver without looking up, and it was over, and he entered it as transient anomia, 1 event.

There were eleven events by the end of month four.

He built workarounds, because that was the thing he did. Describe the function instead of naming the object. Give the dimension. Point. Make a joke, because a joke buys two clean seconds and nobody in recorded history has ever noticed a man being funny to buy time.

He could recite the entire sync-curve dataset from his father's file, every row, including the rows he would have preferred not to have. He could not always retrieve the word spanner.

He hid all of it from his sister.

He hid it badly, because she had been reading faces professionally since she was six, because it was the only sport available to somebody who could not run, because she had spent twenty-two years learning to tell across a room whether the adult walking towards her was going to be kind or careful. Those are different. She could separate them at nine metres.

"Your hand," she said, on day ninety-one, over the ration paste.

"It's cold in here."

"It's twenty-one degrees in here."

"Twenty point four."

"Leon."

"It's a tremor," he said. "It's a coupling artefact. It's a known effect. It's in the dataset and it doesn't progress." One of those four sentences was a lie and he had put it last on purpose, where it would be least examined.

She looked at him for four seconds. He counted them.

"All right," she said.

She had not believed him. He knew she had not believed him, and he knew she had decided to let him have it, and he recognised the manoeuvre, because he had watched her do it in a stairwell with two fingers flat on his sternum, and had understood then that being let have it was something she did deliberately and could stop doing whenever she liked.

"When you're finished," she said. "With the machine and the everything. You owe me a coat."

"I know."

"A real one. Not a blanket with ambitions. Lining. Buttons. A collar that comes up."

"Wool."

"I don't care what it's made of. I care that it fits." She pushed her bowl half an inch away, which was how she declined food now without saying so. "And when I've got a coat that fits, the two of you and I are going to have a conversation about treating me like an adult."

"When you've got a coat," Leon said, "we'll consider it."

She laughed. Three syllables. It cost her; she had to put a hand flat on the table afterward and breathe against the enrichment feed before she could go on, and Pip lifted eleven centimetres off the shelf, thought better of it, and settled.

The joke was eleven years old. It had been funny when she was twelve, in the good rooms at Halcyon with the sun coming across the floor. It was still funny in a hole under a dead world.

That was the whole problem with it.

DAY 131.

The corridor between hangar and habitat, where the light was bad. Garren stopped walking. That was unusual enough that Leon stopped too.

"I served your father eleven years," Garren said.

"I know."

"You know it as a fact. You don't know it. I was in and out of that office nine of those years carrying things, waiting on signatures. Nobody looks at the man behind the desk. That's what a desk is for."

Leon said nothing.

"He was a big man when I met him. Not tall. Big. Laughed at things." Garren looked at the wall, at eighty years of Concord paint. "And every year there was a little less of him at the desk and a little more of him in the work, and you could not point at a day. That's what I want in your head. There was no day. I could not have gone to anybody in year four and said something's wrong with him, because nothing was wrong with him. He was fine. He was better every year. He was solving it."

His lungs caught. He coughed into his fist, twice, the wet click of thirty years of lattice dust, and did not apologise for it.

"Then one afternoon in the ninth year I came in with a manifest and he'd been at that desk since the day before, and he looked up at me, and there was nobody —"

He stopped.

Leon waited.

He did not finish it. He rubbed his mouth with the back of his hand and said, "Eat something," and went on down the corridor, and Leon stood in the bad light for eleven seconds and then went the other way.

DAY 134.

Eighty-one percent. Four minutes eleven seconds, held.

He did nothing with it. That was the run: no manoeuvre, no weapons, no wings. The frame stood on the ash flats with its hands at its sides and its head up, and Leon sat inside it and was twenty metres tall for four minutes and let the board record what that does to a person.

What it does: heart rate one hundred and sixty-one, stable. Cortisol high, not climbing. Nosebleed at two minutes forty, left nostril, minor, ignored. Left-hand tremor at six hertz, unchanged in seventy-nine days. Two hundred and eleven degrees of freedom sitting perfectly still.

Four kilometres away the hangar's standby lattice would be tracking, because it always did now, and he had noticed that and had not looked into it.

The pressure with a shape was there. It was always there above sixty. It leaned on him at a rate he could not hear, and every part of him made of matter was asked, politely, continuously, to agree.

At four minutes eleven he brought it down, let the frame kneel, and took the helmet off in the cold.

Eighty-one point zero.

Full authority: eighty-five.

Ceiling: ninety-one point seven.

Six points between what the machine wanted and what would start writing on him. Six point seven, if you were being exact, and he was always being exact, and six was what he had said to himself for fourteen months, because six was a coin small enough to keep in his mouth.

He had carried that figure across a burning planet, and through fourteen months of the Bellows at four marks a shift, and down a set of cellar stairs on Veridus-9, and up them again. He had never known what it was. He had thought it was talent. Everyone had thought it was talent. There was a version of him, eighteen months old, who had looked at 91.7 sitting above his father's 61.4 and felt something warm and disgraceful turn over in his chest.

It was not talent. It was proximity. It was a measurement of how near his cellular lattice sat to a waveform his father had spent twenty years writing down, and he had 91.7 for one reason, which was that two people had made two children three years apart out of the same materials, and one of them got the whole of it and one of them got a partial, non-lethal expression, and the one who got the partial was sitting on a dead world doing sums.

She got the disease. He got the gift.

There was one thing. It went into two people.

He put it down. He had put it down eleven times in fifty-one days. It came back at the level of arithmetic, unbidden, the way arithmetic always did: 91.7 over 100. The carrier at unity. Sixty percent of design authority. Doubling every forty-two seconds. Under nineteen minutes, cumulative, lifetime.

Four kilometres away, in a hole in a dead planet, his sister was awake, because she was always awake at this hour, because lying down was worse.

Leon sat on the frame's knee in the thin cold with the trench taking the last of the light all the way to the horizon, his left hand shaking at six hertz on his thigh, and a notch in his hearing at exactly her frequency.

Six points.

He went back inside and told her about the run, and about the funnels, and about a joke he had thought of concerning the picket. He told her all of it. It was all true.

He did not lie to her once.

The concentrator ran a two-second cycle. Draw, hold, release. Draw, hold, release.

It had run since month one, when Garren bolted it to the habitat bulkhead and set the sieve beds himself, and it would run until the cells went. Eliana had stopped hearing it the way people stop hearing their own hearts.

She heard it now because she was awake at 0304 and there was nothing else in the room.

She had not slept properly since she was fourteen. Not the way other people meant — not the long unconscious slide from one end of a night to the other. Her sleep arrived in pieces of forty and fifty minutes. Between the pieces she lay flat on her back with her hands folded on her sternum, feeling her ribs work, waiting for the next piece.

Sometimes it did not come. On those nights she counted.

Tonight she counted the module.

Eleven steps from her bunk to the head, taken her way, which was not the way anyone else would have counted them. Four to the partition. A pause with her hand on the frame, because standing up from horizontal cost her something and the frame was where she paid it. Three more to the corner. Another pause. Four to the door. She had measured it in month one and the number had not changed, which she found steadying and did not examine.

The habitat ran twenty-eight percent oxygen at seven-tenths of a bar. Garren had set it and checked it twice a day for four months and had explained it exactly once.

Point one nine bar of oxygen, he'd said. Halcyon at sea level, minus the sea.

Inside the module she could walk to the head without stopping. That was the whole luxury. That was what the sieve beds bought her: eleven steps in one go, like a person.

Outside, the air was Meridian's. She was a different animal out there.

At 2100 they had eaten together, because that was the rule, and the rule was hers.

Garren had put something in the ration paste. Leon noticed on the second mouthful and stopped chewing.

"Pepper," Garren said.

"Four months of grey and tonight there's pepper."

"Yes."

"Was there a reason to wait?"

"No."

Leon let it go, which he did more often now, and turned the conversation to the shoulder. He always turned it to the shoulder. "Cell's laying Gundarium at four hundred and ten grams an hour. Eleven hundred and forty kilos left across the left shoulder assembly and the forearm housing. That's a hundred and sixteen days if the sinter head holds and the feedstock hopper doesn't bridge."

"It'll bridge," said Garren.

"It'll bridge," Leon agreed. He was talking fast and clean, all numbers, no jokes. That was the tell. He was afraid of something he had not said out loud.

Then he looked at her sleeves. The hole in the left elbow had been a snag in Ninepenny and was now a hole you could put a thumb through.

"You've got an elbow with a window in it."

"When I have a coat that fits," she said, "we can discuss whether I'm an adult."

It was an eight-year-old line. It had been funny at fourteen.

Leon took half a second too long. She watched him find the shape of the joke and put it on. "Right," he said. "When I get you a coat."

Garren looked at his plate.

She had let it stand. She had eaten her ration, and made the sound she made when Garren's cooking was bad, and gone to bed at 2200 like a person who slept.

She got up in stages.

Roll to the side. Wait for the room to finish moving. Push up on the heel of one hand. Wait. Feet down. Wait. The deck came cold through her socks and she was glad of it, because cold was information.

Her cardigan was over the end of the bunk. She pulled it on and the sleeves came past her fingers and she pushed them back and they came down again. She had stopped fighting that battle in month six of Veridus.

Leon was asleep on the other side of the partition. He slept in bursts of two hours with long silences between, and it was the silences she listened for, because the wrong kind meant he was lying there working. Tonight the silence was slow and uncomplicated. He had not moved since 0100.

She stood in the dark with her hand on the door frame and let her lungs catch up to being vertical.

Then she went out.

She had mapped the vault by seating.

Nobody taught her that. She built it herself at nine, in the Halcyon ballroom, on the night of her mother's Founding reception: four hundred guests, ninety metres end to end, and eleven places a body could sit without the sitting meaning anything. Three window seats on the east wall, deep enough to look idle. The low bench by the harp. A step in the alcove behind the eastern colonnade that nobody used, with a good angle on the room, and that had been the best of them.

She had sat there in a green dress with her ankles crossed and watched her mother move through a crowd like a hand through water.

She did not let one person, that whole night, watch her look for a chair.

The vault hangar ran ninety-one metres from the habitat hatch to the far wall. She knew every place a body could rest, and the distance to each, and she kept the list the way other people keep keys.

The gantry rail at eight metres. It took weight through the hip, never the hands, because hands looked like need and hips looked like posture.

The equipment crate at nineteen. Garren had set it down there in month two and had never once moved it, and she had a private and entirely unprovable conviction about that.

The step at the base of the fabrication cell at thirty-four, warm when the sinter head was running, which was most nights.

The coolant manifold housing was waist-high and warm on top and stood eleven metres off her line, which made it a seat for somebody else.

After thirty-four there was nothing. Twenty-six metres of open deck plate to the cradle.

Her father had built a hangar for a twenty-metre machine and had not thought about chairs.

She stepped through the hatch and Meridian's air came into her like a thing with edges.

Four-tenths of a bar. Breathable and punishing, Garren said, and Garren used exactly the right number of words. The first breath always felt like a lie: it went in, it filled, it did nothing. The second one told the truth. By the third her body had understood the arithmetic and had started the long resentful business of moving less blood further.

Pip came off the cradle behind her with the wasp sound, ducted fans winding in a jar, and settled at her right shoulder at the height it always chose, which was where her mother used to put a hand.

"I know," she said. "I'm going for a walk."

Two ascending, one flat. Acknowledged, and noted. She had decided that was what the tone meant when she was seventeen and it was almost certainly not what the manufacturer intended.

Its cells held eleven hours now. They had held thirty-one when Sabine Orr signed it out to her.

She started down the gantry.

Here was what she had not told anyone.

In month one, when the crate came off and the frame went vertical in the cradle for the first time, the standby lattice came up in the armour seams. Blue-white, faint, running under the plating like light under ice.

Garren said capacitive bleed. Leon said the micro-repair lattice idling on standby draw. They were both wrong, and she knew they were both wrong inside ninety seconds, because she walked from the base of the cradle to the fabrication cell to get out of their way and the light went with her.

Not brighter. Not a flare. It migrated. Densest on whichever side of the frame she was on, and when she crossed, the density crossed after her over about four seconds, with a soft gradient, the way water finds a tilt.

She said nothing.

In month two she tested it, because she was her father's daughter and her father did not believe a thing until he had made it happen twice on purpose.

She had no photometer. She had segments. The flank plating was laid in twenty-two armour segments from hip to knee and she counted how many carried the glow, which was crude, and repeatable, and hers.

Method: walk a twelve-metre line, north to south, at four standoffs. Do it when Leon was up in the observatory and the extractor in the fab cell was running loud enough to cover a cough.

Results. At eleven metres: nineteen segments, tracking clean, lag under a second. At twenty metres: six segments, lag about six seconds, gradient shallow. At thirty metres: two, intermittent. At forty: nothing she could tell from noise.

Control: she sat on the crate at nineteen and sent Leon down the same line on an invented errand about a torque wrench. Nothing. She sent him again the next day. Nothing. Garren crossed the floor eleven times over the following week on his own business and she watched every crossing and the seams did not flicker.

Not Leon. Not Garren. Her.

She wrote none of it down. She held all of it entire, in the place where she held things, and went up eleven minutes of stairs and ate her ration and said something unkind about Garren's cooking and went to bed.

Then there was Pip.

Pip malfunctioned inside nine metres. She had the figure narrowed to between eight point five and nine point five and could not do better without a rangefinder she did not have.

The malfunctions were not random, and she refused the word strange, because strange was not a diagnostic category and her father would have said so.

Catalogue. Month two: tone sequence corruption. The distress call was three rising, pause, three rising. Inside nine metres it gave three, pause, two — and stopped, as though something had reached in and taken the last note.

Month three: log truncation, twice. The rolling medical buffer ran forty-eight hours. Both times it came back to the charge cradle with the last six hours gone and no error flag raised, which was worse than an error flag.

Month three, eleven days uncatalogued, because she had not wanted to write the sentence.

Pip played back three seconds of her own breathing.

Not the live room. She knew the sound instantly — the hitch on the inhale she got coming off the stairs — and she had not been on the stairs that day. The timestamp, when she pulled it, was eight days old.

Pip had a tone speaker and a diagnostic buzzer. In every firmware revision she had ever read, and she had read all four, there was no audio capture path, no codec, and no sector allocated to store one.

She had held the drone in both hands in the dark of her bunk and felt the fans tick over against her palms.

"That was rude," she told it, and put it back on its cradle.

She told nobody. The reason was two hundred and forty marks.

In month nine on Veridus she had said, once, in passing, that her hands went numb in the mornings. Four words about her own body, because she had wanted somebody alive to know.

Eleven days later the Academy ring was off his hand and there was a new dose regime on the shelf, and he made a joke about the ring being ugly, and never mentioned it again, and believed she had not noticed the pale band of skin.

Her brother converted information about her body into cost. There was no other setting on him. If she said the machine watches me, some price would be paid out of him, in a room she was not in, and she would only find the hole afterwards.

So: no.

So she ran the observations, and kept the numbers, and said nothing, for four months.

Eight metres. The rail.

Hip into the metal, a third of her weight through it, and the hangar laid out below.

Four work lamps on the cradle scaffold, forty watts each. Leon left the two lowest burning overnight and said the fabrication cell needed the thermal load, which was a lie, and did it so she would not walk to the head in the dark, which was the truth.

The light came off the deck plates in long soft sheets of grey. At the far end the frame stood in its cradle with its head down and its left shoulder open to the roof, eighty-two tonnes dry, twenty metres of matte unpainted Gundarium, six cradle clamps torqued to a figure Leon had told her twice.

The seams were dark. They were dark because she was fifty-two metres away.

Nineteen metres. The crate.

She sat properly, both hands flat beside her, and waited out the black spots. In. Out. Further out. Twenty-two seconds. In month one it had been forty.

Getting stronger, she thought, and knew better.

She was under thirty kilos. Last week there had been a new hollow above her left clavicle that had not been there in the summer, and she had looked at it in the polished flank of a coolant tank for about four seconds and then gone and done something else.

She was not getting stronger. She was getting more efficient at being this.

Pip hovered.

"I'm fine."

Thirty-four metres. The fab cell step.

She did not sit. She put one hand on the housing, which was at forty-one degrees where the sinter loop ran under the skin of it, and stood with her weight on the outsides of both feet and let her lungs run. Her pulse held at one thirty-four and would not come down, because coming down needed oxygen, which needed breath, which needed a pulse. Her body had been arguing with itself about that since she was fourteen.

Twenty-six metres of open deck.

Right, she thought. Well.

She went.

She had not crossed twenty-six unbroken metres in Meridian air since they landed. She went at her own pace, which was slower than a very old person's, with her eyes on the plate seams, because the seams ran a metre and a half apart and gave her something to count.

At seam nine the black came in at the edges. She stopped and stood absolutely still with her hands at her sides and leaned on nothing, because there was nothing, and waited for the floor to be a floor.

Forty-one seconds.

At seam fourteen it came again, harder. She got her chin down and her hands on her knees, which she hated, and which nobody was awake to see.

Twenty-eight seconds.

She went on.

At about nine metres from the cradle Pip chirped three rising tones, paused, and gave her two.

"Oh, shut up," she said, smiling, with her pulse going in her ears, because she loved that idiot machine and it had been dropping its last note at her for four months like a bird with something in its throat.

The seams lit.

Not a flare. Her father had never built anything dramatic in his life. Blue-white came up through the plating all along the near side, down the flank, down the shin, into the closed fist that hung at knee height above the cradle deck.

She stopped a metre short and looked up the whole twenty metres of it, at the bowed head and the open shoulder and the feedstock line still coupled at the collar.

"Hello," said Eliana Zadkiel, and put her hand on it.

Her lungs filled.

Her chest went out and the air came in and she waited for the shelf — three-quarters up, the place where breath ended and you turned it around and came back down. There had been a shelf since she was fourteen.

There was no shelf.

The air went past where the shelf lived and kept going, into parts of her she had no map of, and filled them, and there was more room after that. One breath. Four seconds long. At the end of it she was not tired.

She let it out. She took another.

Her hands were warm.

Her hands had not been warm since she was nine. She had known they were cold the way she knew her name had six letters; it was a property, not an event. Now the blood was out at all ten fingertips and they were warm and slightly heavy and they felt like they belonged to some large healthy animal. She turned her free hand over in the air and looked at it and did not know it.

And the noise stopped.

She had not known there was a noise.

It had been under everything, always. A grinding in the substance of her, so constant she had never had a second without it to compare it to.

It stopped.

She made a sound.

She had both palms flat on the plating now and did not remember putting the second one there. Her forehead against the armour. Her eyes open. Warm hands.

Quiet.

Oh, she thought.

This is what all of them have been doing. The whole time.

She thought about four hundred people crossing a ballroom and never looking for a chair. About Garren at two hundred and sixteen with lattice dust in both lungs, whose ruin was a hundred times better than her health. About her brother at nineteen taking a staircase three at a time because he was late for something that did not matter.

She laughed.

It came out ugly and wet and far too loud in the empty hangar, and she pressed her mouth into her own shoulder to kill it, and it came again anyway, and by then she was crying, which was inconvenient, and she did not let go of the machine.

Then she did something stupid.

She kept one hand flat on the plating and walked the length of the flank as fast as she could go — fast, actually fast, the pace of a person crossing a road — and the deck went by underneath and her legs did it without asking her for anything.

At the end of the flank she ran out of machine, and stopped, and stood there hauling air. It was not the bad kind. It was the kind that clears.

There was a length of coolant conduit on the cradle deck. Three centimetres outside diameter, titanium-clad, one point six metres. Eleven kilos.

She had not lifted eleven kilos in seven years.

Her hand came off the armour for the half second it took to bend and get both under it. Waist. Chest. Over her head, arms locked, eleven kilos above a twenty-two-year-old who weighed less than thirty, in a hangar on a dead world, and something in her was shaking hard enough that she could hear the conduit ring.

She ran four steps along the cradle deck with a bar over her head like a lunatic.

Then her hand came off the armour.

It went out the way a lamp goes.

The shelf came back before she finished the step she was in. Lower than before. The air went up and hit it and there was nothing above it at all.

The conduit dropped and rolled and made a great deal of noise and she did not hear most of it.

The cold came into her hands from the fingertips inward. Two seconds. It went to the elbow.

Then the noise came back on, and she heard it arrive, which she had never been able to do.

She got her palm back onto the plating.

Nothing. The seams were still lit. Her hand was flat against them. Nothing.

Not a tap you could turn twice.

Then her nose began to bleed.

She put two fingers under it and looked at them. Bright. It did not slow when she tipped her head.

She got down. Not fell. One knee, then the other, hand out to the deck, controlled, the way she had learned at fifteen when she understood that going down was a thing you could do properly or do once.

More came. It came from her nose and then it came up from somewhere else, and she turned her head and let it go onto the plate rather than swallow, because swallowing meant vomiting and vomiting cost ninety seconds she did not have.

Copper and warm salt. She had known that taste since she was seventeen.

She knelt with her hands flat on the cold plate and let it run.

She was not frightened. She was working.

Contact: call it four minutes. Say two hundred seconds, be conservative.

Onset: under twenty seconds from break.

Volume unknown. Estimate later, against the stain.

Nose and lower. That is two sources. That is not a vessel.

So it is not free.

So it is a trade.

That did not surprise her. She had been paying for things out of her own body since she was fourteen — every stair, every argument, every hour spent being a person in front of her brother, all of it billed and settled the same night. The universe had never given her anything free and had not started now.

The price was not the novel part.

The novel part was that this time she had been given something worth it.

I don't know the mechanism.

And then, flatly: I don't need to.

She knelt until the bleeding slowed, which took a while. She counted her pulse against the seconds. One fifty-two. One forty. One twenty-nine.

Survivable. She got to work.

There was a rag in the fab cell housing and a solvent bottle beside it, thirty-four metres back. She used the hem of her skirt.

It was white. It had always been white. Meridian was dry and the blood had gone tacky at the edges and came up better than she expected. She scrubbed the plate with her knuckles inside the fabric until the metal came back grey. Then the second patch, a spray of it two feet off, which she had nearly missed.

Then she sat on her heels and looked at the deck from the height her brother would be standing at tomorrow, and from the height Garren would be at, crouched over the coolant runs.

She did both patches again.

Her face she did with her sleeve. The cardigan was old enough that another mark on it meant nothing.

Her hands she did last, one at a time, the seams of the knuckles and under the nails, because Leon looked at her hands. He had done it every morning since Veridus, across the ration table, one glance, half a second. He thought it was invisible.

The skirt she would wash at 0500 in the grey-water line, when neither of them was up.

Then she called Pip down into her lap.

The diagnostic port was under the left fan housing. She got it open with her thumbnail. The fans dropped to idle and the drone lay in the hollow of her skirt like something asleep.

Her hands were steady.

Rolling buffer, forty-eight hours. She found the window. 0304 to 0349.

She did not delete it. A gap in a medical log is a flare on a hillside, and Leon found everything inside a week.

She overwrote it. She pulled the matching forty-five-minute window from eleven days back — a night she had actually slept, respiratory trace flat and clean, resting pulse ninety-one — and wrote it forward into tonight's slot. Then she walked the timestamps by hand, one at a time, so the drift matched the drift Pip's clock actually had, which ran nineteen milliseconds fast per hour and always had.

Then the block hash on the segment header, which would not match, and which she recomputed and wrote in.

Nine minutes. She had done it before. Twice on Veridus, when the numbers were bad enough that he would have sold something.

The last thing was the audio sector Pip should not have had. It held a hundred and four seconds now. Not three.

She did not listen to it. She zeroed the sector, wrote noise across it, closed the housing with her thumbnail and put the drone up into the air.

It hovered. It chirped. Three rising, pause, three rising. All six, in order, at nineteen metres.

"Good," said Eliana. "Better."

She stood up.

She did not remember most of the floor.

She remembered the crate at nineteen, and sitting on it a long time with her head between her knees, and having a serious internal argument about whether she could sleep there and get up before him. She lost it. Leon woke at 0530 and came out to check the fabrication cell first thing, every day since month one, and pretended it was about the cell.

The stairs were eleven minutes.

They were always eleven minutes. On a bad night they were fourteen and she did not have fourteen in her, so they were eleven, and she made them eleven, both hands on the rail, her weight going up through her arms because there was nothing left in her legs.

Twenty-two steps. She rested on eight, eleven, fourteen, sixteen, seventeen, eighteen, nineteen, twenty, twenty-one.

On nineteen she thought, quite clearly: if I stop here he finds me in two hours.

She did step twenty.

At the top she stood outside the hatch for a full minute and got her breathing down to something that would not carry through a partition. She got it there. She had been managing the sound of her own breathing in the vicinity of her brother for eight years and she was better at it than he would ever be at anything.

The habitat air came over her when the hatch opened, and it was like water.

The concentrator was still running. Draw, hold, release. The silence past the partition was still the slow kind. She checked, at the corner, the way she always checked. He had not moved.

She put Pip on its cradle and it settled and dimmed itself down to nothing, so as not to be a bright thing in a dark room.

She got into her bunk in four stages, pulled the blanket up, and lay flat on her back with her hands folded on her sternum and her mother's ring turned round so the sunburst sat on the back of her hand.

The wall was cold against her shoulder. Her brother was eleven centimetres away through it, asleep.

Astraia, she thought.

She had said it at the door in month one, in the old language, the way Elizabeth taught it to her when she was six. The long open vowel at the front. Leon had never once got it right, not in twenty-five years, not even on purpose, and the door had opened for her and not for him.

Her mother had taught her one word and had not taught it to her brother, and they had laughed about that at table for years.

Mother, she thought. You taught me a key and called it a word.

She closed her eyes.

The number was 88.0 and it had been 88.0 for nine minutes and forty seconds, and Leon could feel every one of those seconds sitting on him like coins.

Session sixty-one. Day nineteen of the picket cycle, which meant no drives, no field, no output of any kind a hull sensor at two AU could resolve. Cold coupling only. The vault plant fed the frame forty-four kilowatts through a grey umbilical thick as a man's thigh, and forty-four kilowatts ran the standby lattice, the couch, the coolant loop, and nothing else.

It was enough. It had always been enough. The Psycho-Frame did not need power to reach him. It needed proximity, and it needed permission, and four months had gone into learning to give it less permission than it asked for.

He lay in the dark inside the torso with his eyes open on nothing.

There was no interface. That was the whole of it — the thing the Reach had never built and had died for not building. No collar. No implant. No eighty-millisecond handshake, no Halo governor politely asking his motor cortex to say that again. The frame hung in the armour as particulate at nine parts per million by volume, and the couch shell was seeded with the same particulate at a hundred times the density, and between the two there was a field, and inside the field his nervous system and the machine's lattice were one continuous structure with no lag in it at all.

Zero. Not low. Zero. His father had solved a problem nobody else had managed to state.

Which meant that when the frame moved, Leon did not command it. Leon was it. And when Leon breathed, the internal pressure sinks along the torso tried, very faintly, to breathe with him.

Hold the seam.

That was his word for the place where he stopped and the machine started. It was not a physical place. After four months he knew it the way a man knows the exact spot on a bad tooth. Below eighty percent the seam was a wall. At eighty-five it was a curtain.

At eighty-eight it was surface tension.

"Coupling eighty-eight point zero," Garren said in his ear. Flat. "Nine forty. Come down."

"I'm fine."

"You're at one forty-eight."

"Heart rate's a personality trait."

"Core temperature thirty-eight nine. Couch jacket's pulling forty litres a minute of glycol at four degrees and it is not keeping up, which means you are making more heat than a two-hundred-kilo man." A pause. "Come down to eighty-two. Hold it twenty minutes. We go again Thursday."

Leon did not answer. Answering cost attention, and attention was the only currency in the room.

The frame's left hand rested on the cradle rail. He could feel the rail. Not as telemetry — as cold. Through fingers eight point four metres long, the granular cold of old cast steel with condensation on it in a chamber at four degrees, and the microtexture of eighty years of paint under the condensation. He could feel the mass of his own forearm. The mass was two hundred and eleven tonnes and it sat correctly in his sense of himself, which was the problem.

Somewhere under it there was a man who weighed seventy-one kilos and had weighed seventy-eight in month one, and who had to keep believing the seventy-one was the real number.

That was high coupling. Not visions. Not voices. An argument about which body was his, conducted continuously, by a machine that never got tired.

"Eighty-eight point one."

"I want ninety."

"You want to be dead."

"Ninety's inside the number."

"The number is a dead man's arithmetic and you know whose."

There it sat, in the room, the way it always did. Ninety-one point seven. Seven hundred pages of curve in the third file of a package that had come with no message in it, and one line of that curve was Leon. Above it the coupling inverted. The return path opened, and the frame stopped reading him and started writing him.

Below it, in his father's neat and murderous notation, he was safe.

Unit-02 needed eighty-five for full authority. Everything above eighty-five was margin. Margin was where the fighting happened. He had six point seven points of it and he had been carrying that fact for fourteen months.

He thinned the seam.

Not a push. There was no pushing. It was closer to unclenching a muscle held since childhood, and he did it in increments the size of a held breath.

"Eighty-eight four."

The chamber came up around him.

Ninety metres of rock. Thirty across. Ceiling at twenty-six. The survey crews had rolled a five-metre grid onto the floor eighty years ago in safety orange and it had gone the colour of a healed scar. He had all of it at once, through his skin. The fabrication cell at the far end running its third-shift cycle at sixty-one percent duty. Four hundred and eleven kilos of feedstock in the third drum. Six fin funnels racked and dark and cold enough to read as holes. The gantry. A dropped spanner under square nine that had been there since month three, that neither of them had picked up, because picking it up meant admitting it mattered.

"Eighty-nine point one."

Somebody blinked and the optics irised down two stops. Leon was reasonably sure the somebody had been him.

"Eighty-nine four. Leon. Down."

"Little more."

"That's not—" Garren stopped, and did the thing he did instead of coughing, thirty years of lattice dust held behind his teeth out of pure spite. "Your left hand is tremoring at four hertz and the frame is copying it. Two hundred tonnes of forearm doing your tremor. Cradle rail's rated four hundred megapascals and you're putting cyclic load into it at four cycles a second."

"Send the strain log to my quarters."

"Eighty-nine six."

Almost. His mouth had gone metallic. His jaw ached around the guard. He had not slept the way sleep was supposed to work since month one, because when he closed his eyes the seam was thinner and the frame was always awake — patient as weather, sitting there at eleven percent standby, waiting for him to leave a door open.

The airlock cycled.

He heard it twice.

Once with his ears, muffled through the hull and the couch shell — the dull thud-clack of the personnel door throwing its dogs. And once through the frame's hull sensors, which logged the pressure step of enriched air spilling out into 0.4 bar as a delta of thirty-one millibars across the apron.

Both arrived in the same instant. There was no lag. His father had solved the problem. And Leon's brain had no procedure for a sound that was in two skulls at once.

Then the lattice indicators turned.

They ran along the frame's spine and inner shoulders in a line, forty-one of them, standby telltales whose entire job was to glow at eleven percent and mean nothing at all. He knew what they looked like. He had looked at them a thousand times from outside.

They turned toward the door.

All forty-one. Together.

"Ninety point eight," Garren said, and his voice had changed shape.

Leon had not moved. He wanted that recorded somewhere. He had not thinned anything, had not unclenched, had not reached. The number left him behind.

"Ninety-two point six."

The seam did not break. It stopped being relevant, the way a fence stops being relevant when the field decides to be somewhere else. Something enormous went past him and was not interested in him at all.

His left arm came up.

Both of them — the eight-metre one and the one that was actually his. The cradle locks took the load and screamed about it, a note in the steel he felt in his molars.

"Bus draw," Garren said, and then, differently, "the bus is at nine kilowatts."

Nine. To move two hundred and eleven tonnes of forearm through thirty degrees in under two seconds was a shade over nine hundred kilowatts, and Leon had that figure before Garren finished the sentence, and the umbilical was delivering forty-four, and the breaker had not tripped, and none of it was arriving from anywhere on the plant schematic.

The lattice was drawing from somewhere else. Leon knew exactly where.

He could not remember the word for it.

He could not remember the word for sister.

He had pi to two hundred and six places. He had the tessamine schedule to the milligram. He had the mass of the third feedstock drum and the yield strength of the cradle rail. He did not have the word.

"Ninety-four point one. Leon. Answer me."

His diaphragm went. Not stopped — taken. Somebody else was breathing him on a rhythm that had nothing to do with lungs. His heart came off its rails at one hundred and ninety-one. The frame leaned, and past the shoulder plating, sixty metres down the orange grid, in the wash of the door lights, there was a small white shape standing very still with one hand flat on the bulkhead.

Eliana.

Word retrieved. Nine seconds late.

The frame reached for her, and it reached through him, and for one clean and unrepeatable moment Leon understood that he was not the pilot of this machine. He was the length of wiring that happened to be in the way.

"Ninety-four point nine—"

Garren hit the bar.

He had bolted it to the console himself in month two, a length of brass off the Dray's old bridge, because he did not trust software to be frightened at the correct time. The umbilical breaker went. The field collapsed inside forty milliseconds.

Leon lost everything at once.

Not darkness. Amputation, in every direction simultaneously. The floor, the rock, the drums, the spanner, the eight-metre hands, the two hundred and eleven tonnes — all of it taken off his body without anaesthetic, and what was left behind was seventy-one kilos of man in a shell at eleven degrees, screaming into a mouth guard.

The hatch took him three tries. His hands would not agree about which of them was doing it.

He got it open, got the ladder, got four rungs down, and then the rungs were not where his feet said they were and he went the rest of the way and landed on the grid on his hands and knees.

He was sick between his own fingers. Twice. His nose was bleeding hard enough that it went into the sick and made a pattern, and some clerical part of him noted the ratio and filed it. His left ear rang at a pure tone he put at 4.2 kilohertz. The tremor in his left hand had stopped being four hertz and become something with no frequency at all.

He knelt and breathed the thin cold air, and it was like drinking through gauze.

Boots. Garren's, unhurried, which was Garren for running.

"Don't move him," Garren said to nobody, and then, "don't move, boy."

"I'm fine."

"You're bleeding out your left ear."

"That's the ear that does that."

Garren crouched. His knees cracked. Two hundred and sixteen years old and his knees still cracked; he had said once that they had been at it since the fourth century and he had stopped taking it personally.

"Ninety-four point nine," he said. "Three point two over your ceiling. Held for six seconds."

"I know what it held for."

"You don't. You weren't there for it. I was there for it."

Leon got one foot under himself. The floor tilted eleven degrees, apologised, came back.

Sixty metres away, the small white shape had not moved off the bulkhead.

He went at Garren first, because Garren was closer.

"Who opened the door."

"She did. Same as she opens every door in this hole."

"There's a lockout—"

"There's a lockout on the drive bay. Not on the hangar. You wrote the permissions." Garren stood up slowly and wiped his palm down his thigh. "Month two. I said put her behind a code. You said it would only hurt her."

"So you watched her walk in."

"I was watching you." The old man's voice did not rise. It never did. It got shorter, that was all — the words trimmed until there was nothing soft left on them. "I was watching a number I have watched exactly once before in my life."

"Don't."

"I sat the board for your mother's last three sessions."

"Don't."

"Sixty-one point four. She was frightened of it. She went anyway, and she—"

Leon hit the cradle rail with the flat of his hand. It did nothing to the rail. It split the heel of his palm and he did not notice for some minutes.

"Two hundred and sixteen," he said. "You'll bury both of us and go and buy another shop. You've got the face on. That's the face of a man who's already worked out what he does after."

Garren looked at him and said nothing whatsoever, which was the worst answer available, and Leon turned round because there had to be somewhere else to put it.

She was just inside the door, on the enriched apron — twelve metres of floor where the habitat overflow spilled out and it was almost warm and almost breathable. The white cardigan two sizes wrong, hole in the left elbow. The white skirt. The sneakers, grey now. Everything on this world went grey.

The bottle on its shoulder strap. Forty minutes at low flow. The mask hanging at her jaw.

Pip hovered above her left shoulder, ducted fans buzzing in the thin air like a wasp in a jar, drawing hard to hold altitude at 0.4 bar on cells that were already down to sixty-eight percent of rated capacity.

"Go back inside," Leon said.

"Leon—"

"Go back inside."

"I heard the—"

"You heard nothing. You were told. Month one, first week, the one rule, the only rule in this entire—" his voice cracked and came back a note high "—you do not come into the hangar during a session. You don't come near it. And you walked in at eighty-nine six with your hand on the wall like you're deciding what to have for dinner."

"He doesn't shout." Her voice arrived thinned by sixty metres of bad air. "He was shouting."

"So you did eleven minutes on the stairs."

"Nine."

"Nine minutes." He laughed, and heard it be ugly, and did not stop. "Nine minutes of what you've got, spent on coming down here to look at me. You sat at the top of those stairs and you did that sum. That's what you decided to buy."

Pip's lights dropped to a dim amber. It did that in dark rooms so as not to be a bright thing in one. It did it now, and Leon hated it.

"Leon," Garren said, behind him. Just the name.

Leon did not turn round.

"You know what it did? Just now. It went past me. Four months I've been in that seat learning how to hold a door shut with my whole body, and you walk in, and it goes straight past me like I'm—" He stopped. He had come very close to the edge of something eighteen weeks deep, and he stepped back off it, and stepping back cost him whatever he had left. "You are not to be in this room. Any other room on this planet. Not this one."

"Why?"

Because it wants you. Because it was built out of the shape of you and it knows the shape, and I have known since month one, and I have said it to nobody. Not to him. Not to you. Not out loud. Not once.

"Because I said."

"That's not a reason. That's the noise you make when you haven't got one."

That was what did it. Because it was her, completely her — twenty-two years old, under thirty kilos, quicker in an argument than anyone who had not met her would credit — and he was four months without sleep with blood drying on his lip and a machine's fingerprints still inside his chest.

"Do you know what I've spent," he said.

"Leon."

"No. You get this one. You've never had this one." He took two steps toward her and stopped, because walking was still negotiable. "I have never had a day. Not one. Not since I was three years old and they put you in my arms and said mind her head. Every hour I've had has been yours. The Bellows was yours. The ring was yours. Fourteen months of thirty-one marks a week was yours." His hands were shaking badly enough that he put them behind his back. "You want to walk everywhere on your own, fine. Nobody carries you. That's the rule, that's the famous rule. I have carried you every day since I was three. I just did it where you couldn't see, because you'd have made me stop."

Her mouth opened. Nothing came out of it.

"And the whole time," Leon said, "the actual arithmetic of it. You are going to die anyway."

The fabrication cell hummed at the far end of the chamber. Nothing else made any sound at all.

"Two years. Orr said two years, probably less, and she said it in that voice, and I did the sum in the corridor after and I've done it every day since and it does not improve. You're going to die and I'll still have spent it. All of it. That's the shape of my life. That is the entire shape of it, and I'm not allowed to say so, because you're ill, so everybody gets to be gentle at me forever—"

"Stop."

"—and when you get a coat that fits," he said, "we'll all consider treating you like an adult. That's the joke. That's your joke. You've been doing it since you were nine." His face was wet and he had not registered it happening. "You're twenty-two. You have never owned a coat. I promised you one. I'm not going to get you one, and everyone standing in this room knows it."

Quiet.

Pip, dim. Garren, somewhere behind him, a man made entirely of not moving.

Eliana came off the bulkhead and started walking.

Sixty metres. Twelve squares of faded orange, five metres to a square.

He counted them without deciding to, the way he counted everything, the way he had counted fifteen seconds of arc in four minutes eleven days before the invasion and got the mathematics right and the conclusion wrong.

Square one. Square two.

She was still on the apron, still in the enriched, walking the way she walked — not slow exactly. Measured. Like someone carrying a full cup across a room. Left, a fraction of a pause, right. Chin up. She had always walked with her chin up. Their mother's doing.

"Go back," Leon said.

Square three.

"El. Go back inside."

Square four.

"There's nothing down here. There's nothing to come and see. I'm standing up, look at me, I'm—"

Square five. At the edge of it the apron ended, and Leon watched his sister walk out of the last of the good air with the mask hanging at her jaw and not reach for it.

"Put the mask on."

She kept coming.

"Eliana. Put the mask on. It's four hundred millibars out here."

Square six. Thirty-five metres. Pip came with her at her shoulder, fans up an octave, pulling current it did not have.

She stopped.

Not a stagger. She stopped the way a person stops to look at something. Weight on the left foot, standing in the middle of the grid, and Leon could see her chest going — small and fast, the shallow rapid thing that meant she was getting about half of what she was asking for. Her hands hung at her sides. The signet had turned on her thumb, sunburst sitting on the back of her hand, where it always ended up.

Twelve seconds. He counted those too.

Then she picked her left foot up and put it down thirty centimetres further on.

"Don't," Leon said. There was nothing behind it.

Square seven. Square eight.

Somewhere in square eight he stopped shouting, because he had run out of things that were both true and sayable, and because he had begun to understand what he was looking at.

She was doing it in front of Garren.

Month two, third week, when the ramp iced and he had picked her up and carried her nine metres to the airlock. She had waited until the door was shut and then said it once, quietly, with her hand flat on his chest. Never where anyone can see. Not never. Never where anyone can see.

And Garren counted. Garren was the entire population of anyone on this planet.

Square nine. Twenty metres.

His legs told him to go. Every part of him told him to go — three seconds at a run, pick her up, it would cost nothing, she weighed less than the spanner crate.

He did not move. She had not asked. If he crossed those twenty metres and took them off her he would be taking the last thing she owned outright, and she would let him have it, and she would never once mention it, and it would sit between them for the rest of her life, which was two years, probably less.

He stood at the foot of the cradle with his hands at his sides and let his sister come to him.

Square ten. Fifteen metres.

Pip failed.

Nine metres from the frame's foot the fan note dropped an octave. The drone yawed hard left, corrected, yawed again, then hauled itself backwards out of the field like something wading out of a river. Its lights strobed once. It hovered at the edge of square nine and would not come further, and Leon watched it try twice more and give up.

Eliana did not look at it.

She had known that would happen. He understood, in the fraction of a second available to him, that she had known — which meant she had been this close to the frame before, on her own, with nobody on the board.

Square eleven.

She stopped again.

This one had a stumble in the front of it. A half-step where the right knee did not lock. She put her hand out and there was nothing there to put it on, and she stood in the middle of an empty painted square with her arm extended at nothing.

Leon made a sound. He did not know what it was.

She got the arm back down. She turned her head and looked at him, and her eyes were indigo all the way through, which happened when she was frightened.

She was not asking permission. She was checking that he was still watching.

Then she came the rest of it.

Ten metres. Eight. He could hear her breathing now, and it was not a good sound. There was a click at the top of each one, an airway that had already done this too many times today, and under the click a wet edge he had been listening to for fourteen months and had learned to hate more than any noise in the universe.

Five. Two. One.

She stopped in front of him, close enough that he had to look down, and put both hands flat on his chest, and Leon understood that she was not holding him.

She was holding herself up.

She was crying. That was the thing that took the floor out.

Eliana Zadkiel had not cried in front of him since Lumengarde. Not at Orr's. Not at the silo with her own face two metres high on the side of it. Not once in fourteen months of tessamine and stairs. She was crying now with no noise in it at all, water going down a face that was too small for the bones in it.

"Stop," she said.

"El—"

"Not careful." She had to break it up to get it out. "Everyone says careful. I'm not—" a breath "—I'm not saying careful. I'm saying stop."

"I can't."

"He did this." Her fingers curled into his shirt. "Papa. He sat in a room and he did sums. About me." Breath. "Twenty years. He never came upstairs and said one of them out loud." Breath. "Then he got into the thing he built out of the sums and it took an hour. And there was no message. I didn't get to say anything to him. Not one thing."

"El, please—"

"You've got his handwriting." Shaking. "Exactly his. You go quiet and you go precise, and I know what that looks like from outside. I watched it my whole childhood."

She got a fistful of shirt in each hand.

"I've got two years. You've got sixty." Breath, a bad one. "I don't want to be the thing you were spent on. I never asked to be that. I'd rather be dead than be that."

"Don't—"

"Ith'varan." It cracked in the middle. "I'm not asking you to be careful. I'm asking you to be here."

Leon stood with his hands empty at his sides.

"Ith-varán," he said, mangling it, the way he had at nine years old at a table in Lumengarde while their mother laughed into her hand.

"Ith'varan. You always put it on the wrong end."

Her mouth did something. It was not a smile. It was in the family of smiles.

Leon's anger went out. Not slowly. It went out the way a light goes out — all at once, complete, leaving the room exactly as full of objects as before and none of them worth anything.

He put his arms around her and picked her up.

Not the careful way. Not the invalid lift with one arm under the knees. Both arms under hers, hands locked behind her back, and he stood up straight and took her clean off the floor.

Her sneakers came away from the grid. Her chin went past his shoulder. Her feet hung.

It was their father's hug, and both of them knew it in the same instant. Leon felt her know it. Aria Zadkiel had never once in his life bent down to a child — he lifted them, arms under, feet clear, the whole small weight of them held against his chest. He had done it in the doorway of the study at three in the morning with his eyes wrecked. He had done it on the terrace. He had done it, absurdly, to a fifteen-year-old Leon who was already taller than the bannister.

And he had always guessed the weight out loud. Solemnly, like a customs declaration. Twenty-six point four. And been told he was wrong, and refused to revise.

Leon did not say a number. He had one. It came up unasked, out of the load on his forearms, and it began with a two and it was not twenty-nine any more. He put it in a drawer at the back and stood on the drawer.

He had not done this since Lumengarde. Since a house with a garden in it.

"I'm sorry," he said into her hair. "El. I'm sorry. None of that was— I haven't slept, I haven't slept properly since we got here, I know I'm not right, Garren's been saying it for weeks and I've been laughing at him."

She had gone very still against him.

"We'll stand the sessions down. A week. Two. I'll bring the number down, I'll take it to eighty, I'll take it to seventy, El, I'll—"

Her chest was against his shoulder and her chin was past his ear and he had her whole weight, which was nothing.

So he did not feel it.

He felt only that she had gone quiet, and quiet was what he wanted. He kept talking into it, low and fast, the way he had talked to her through the wall on Veridus-9 on the bad nights. Saying her name. Saying it was all right. Somewhere in it he registered that his back was warm.

Then he noticed she was not holding on any more.

Her arms had come off his neck. He did not know when.

He said her name.

He set her down and she did not take her own weight.

He got a hand under her. There was blood on it. It had come off the back of his own jacket. He turned the hand over.

He could not work out whose it was.

Garren crossed sixty metres in eleven seconds, which was not possible for a man of two hundred and sixteen with those lungs, and did it anyway, and said nothing when he arrived. He got her under the shoulders. Pip came in from square nine the instant the field let it — three rising tones, pause, three rising tones — a sound it had made perhaps forty times in her life and that Leon heard now from a distance of forty centimetres.

The habitat. The bulkhead. The bunk in the second module with the good seal. The concentrator at maximum and then above maximum, which it had a setting for and was not supposed to have, and the tone it made at that setting, which was new. Orr's protocol out of the locker. The packs he had bought with the ring money. Garren's hands, which did not shake.

The vault ceiling above all of it. Raw rock, sprayed sealant, eighty years old, a hairline crack running from the light fitting to the corner that Leon had looked at every day for five months and had never once seen.

They put him out of the room. He did not fight it.

He sat on the floor of the corridor with his back against the wall, in the enriched section, where the air was thick enough to be free.

Someone had taken his jacket off him and given it back. It was the grey one from Ninepenny, canvas, the one he had worn on the Bellows for fourteen months. The back of it was soaked through and going tacky at the edges.

Dry, that jacket massed one point one kilos. He knew because he had weighed it in the Dray's hold in month two, against the mass budget, when they were arguing about what to bring.

He lifted it now and shifted it in his hands, twice, the way you do. A little over one and a half.

Call it four hundred and twenty grams. Whole blood at one point zero six. Three hundred and ninety-six millilitres, and that was only what the canvas had kept. The grid had the rest of it, and his shirt, and the floor.

Circulating volume, sixty-five to seventy millilitres per kilogram. She was twenty-seven point four. There was no point in the drawer any more. One point eight litres in her on a good day, and this had not been a good day.

Twenty-one percent.

He sat with the wet coat across his knees and waited for the number to tell him what to do next, and it did not, because that was not what numbers were for.

He checked it. He always checked.

It was right.

He did it again.

The concentrator ran at thirty-one percent.

It had run at twenty-six for four months, which was already high — high enough that Garren had cut a second intake through the habitat's north wall in the first fortnight and sleeved it with eighty-year-old survey ducting, because Meridian-7 delivered its atmosphere at 0.41 bar and gave up the oxygen in it unwillingly. Two sieve beds. Ninety-second cycle. Twenty-six percent had been the number Leon had learned to hear in the pitch of the compressor from three rooms away, the way you learn the sound of a healthy engine.

Thirty-one had a different pitch. Higher, with a thin whine riding under the churn.

He stood in the door of her room on the hundred and thirty-first day and read the wall panel instead of looking at her. He had already looked at her twice this morning.

Cannula flow: 2.4 litres a minute at rest. It had been 1.1.

Saturation on that flow: ninety-one. It had been ninety-six on nothing at all, in a garden, on a planet that no longer had a garden.

Resting heart rate: 118.

Mass: 26.9 kilograms. Four days ago, 28.4.

She had not lost one and a half kilograms of anything a person could afford to lose. His head ran the slope without being asked, produced a rate, produced a date, and offered it to him. That was the arrangement he had with his own head. It had never once been renegotiated.

Grip strength, left: 4.1 kilograms. Right: 3.8. On Veridus-9 in month nine it had been 7.2 and 6.9 and she had used the numbers to win an argument about a jar.

She could not do stairs. Not slowly. Not at all. The eleven minutes were gone. They had been eleven minutes of open war with her own legs, defended for two years against every arm anybody offered her, and now they were simply not available, the way a road is not available.

There was a stick leaning against the bed frame. Garren had turned it down out of a length of instrument tripod from the observatory and wrapped the grip in cargo strapping so it would not be cold under her hand. She had not touched it yet.

"You're reading my numbers," she said.

"I'm reading the wall."

"The wall is my numbers." Her voice came from lower in her chest than it used to. "Say them out loud so I know you're not rounding."

"Thirty-one percent. Two point four. Ninety-one."

"And the weight."

"You know the weight."

"I want to hear whether you say it fast," Eliana said.

He said it at exactly the speed of a man saying a number. "Twenty-six point nine."

She lay against three pillows in a bed she hated with a completeness he found genuinely impressive. The cardigan was on over the gown Sabine Orr had left them two ports ago, white on white. The hole in the left elbow had gone through to a rip — four centimetres, fraying at both ends. Her hair was on the pillow. Her hands were flat on the blanket, and the signet had turned again so the sunburst sat on the back of her thumb like it had been placed there by somebody with an opinion.

Pip sat on the shelf above her head with its lights down to a quarter. It had been doing that since the fourth day. It dimmed itself in rooms where somebody was sleeping and had apparently decided this room qualified permanently.

Leon crossed and straightened the blanket over her feet. It did not need straightening.

"Garren wants you in the hangar," he said.

"Garren wants me in a coffin-shaped chair with a strap across it."

"That's a bench."

"It has a strap, Leon."

"It has a strap because you fainted on it."

"I sat down," Eliana said, "with unusual speed."

He laughed. It came out mostly right. She watched him do it — she had started watching him do things — and then let it go past.

"I want up."

"You're up. You're vertical from the ribs."

"I want out." She stopped, took the top half of a breath, and went on at a lower volume. "Four days. I have counted the ceiling. Nine hundred and forty-one perforations in the acoustic panel. Eleven are blocked. One of them has a spider in it, on a world with no spiders, which means it is a piece of somebody's glove from eighty years ago, which means I have spent four days looking at a dead man's finger."

"That's the argument, is it."

"That's the preamble. The argument is that I would rather be in the hangar being condescended to by a two-hundred-and-sixteen-year-old man."

"He'd tell you to rest."

"He'd tell me to rest and then hand me the coolant log, because he can't help himself." She got her elbows under her, made four centimetres, stopped. Held there. "Help."

He helped.

She weighed like a folded coat. His arms had learned the figure before his mouth had.

"When I have a coat that fits," Eliana said into his shoulder, sixteen months of the joke worn down to bare metal, "we'll consider treating me like an adult."

"That's the arrangement."

"That's the arrangement." She got her hand around the stick and did not remark on the fact that she was doing it. "Bring the small bottle. I'm not going down there on the wall supply and I'm not being pushed."

The small bottle was a 1.4-litre aluminium cylinder at 200 bar. Two hundred and eighty litres of free gas. At 2.4 a minute that was a hundred and sixteen minutes, less the regulator's fixed loss, less whatever she spent on the ramp.

A hundred and eleven minutes. He did not want the figure either. He got it anyway.

Sixty-one metres of corridor, then the ramp: nine degrees over eighteen metres, cut by a survey crew who had never intended to walk it twice.

She did it in fourteen minutes and forty seconds. Leon knew because he had started the count at the door out of the habitat and could not make himself stop it, and because at metre thirty-two she went from three steps between pauses to two, and at the top of the ramp she stood with her weight through the stick and her free hand flat on the rock and did nothing at all for twenty-five seconds while her saturation came back up off eighty-eight.

He walked at her shoulder and talked about the feedstock inventory the entire way, because if he stopped talking she would hear herself breathing.

"There's a trolley," he said, at metre fifty.

"There is."

"It's a very good trolley. Rated four hundred kilos. You'd be an insult to it."

"Then it can be insulted upstairs, where it lives."

The hangar was cold in the way that only a room cut out of rock is cold. No wind in it. No opinion about you.

Unit-02 stood in the cradle at the far end under nine metres of gantry. Ninety-six percent complete. The fabrication cell along the west wall was laying finished nanolattice at a hundred and eight kilograms a day and had been for eighteen weeks, and the armour had come up the previous week, so the frame no longer looked like a skeleton with intent. It looked like a thing.

Twenty metres of Gundarium Epsilon under a nano-laminate that took the work lights and returned almost none of them. Matte white that read grey in this room. Shoulder blocks open and unfinished. A loom of cabling still hanging out of the left hip like a dressing nobody had changed.

The cradle load cells read 41.8 tonnes dry, no drives charged, no ordnance.

Under all of it, the Psycho-Frame. Full body. One to one. Zero lag, against the eighty milliseconds that had killed eleven million people in ninety minutes.

The standby indicators ran in a line along the collar and down the inside of both forearms. Thirty-one amber points, cold-idle, four hundred watts, holding the lattice above its set temperature so it would not crystallise out and have to be scrapped.

Leon had watched them do a thing he had never entered in a log.

Garren was at the VEDA terminal with a mug he had not drunk from. He had the cough today — the flat one out of the bottom of him that meant lattice dust and thirty years of it — and he put it into his shoulder like a maintenance task.

"Sit her down," he said, without turning.

"I can hear you," said Eliana.

"I know."

She sat on the bench with the strap and did not put the strap on. Leon set the bottle on the deck by her foot, ran the line, dialled 2.4, and checked it twice. Once more than necessary. She noticed.

"You need to see this," Garren said.

"You've been at that all night."

"VEDA's been at it all night. I've been watching it be at it." He tapped the pane. "Sit down, boy."

Leon sat.

He had had a hundred and twenty-two days to prepare for a moment like this one and had spent a great many of them designing the face he was about to wear, and his pulse still went up eleven beats when the plot came up.

VEDA rendered it flat and grey and without ceremony. A local terminal off a probability engine did not know how to be dramatic. It had four months and every log line in them.

COUPLING EFFICIENCY — 1,411 EVENTS / 63 SESSIONS / D1–D129. REGRESSED AGAINST 218 LOGGED VARIABLES.

Then a sorted column of coefficients, and the top of it was not what the top of it should have been.

Pilot sync index, r = 0.31. Coolant loop delta-T, r = 0.09. Photon battery state of charge, r = 0.04. Ambient lattice temperature, r = 0.02.

And above all of them, alone, with a gap under it like a step:

UNMODELLED PROXIMAL MASS (26.9 kg). INVERSE-SQUARE RANGE TERM. r = 0.94.

The scatter did what scatter does when it is telling the truth. It was not a cloud. It was a curve. Coupling efficiency against distance to mass — flat out past twenty metres, climbing off the floor at eighteen, going up hard inside twelve, and at nine metres it stopped behaving like the graph of a machine.

Leon looked at it.

He made himself take it in the wrong order, which is how people take things in. He read the axis labels last. He leaned in. He put his finger on the pane — he had never in his life needed to point at anything.

Three seconds. Then ask something.

He had four questions available. The best one was what happens to the exponent above eighty percent authority. That was the question of a man who had already been down the road and knew where it bent.

He asked the third-best one.

"Unmodelled proximal what?"

"Mass," said Garren.

"It's calling a person a mass."

"It's calling a person a mass because nobody ever told it what a person is." Garren pulled the session index up beside the plot. "Sixty-three runs. I logged the lot. Where everyone was standing, what we'd eaten, what the compressor was doing, what the rock was doing. VEDA's had it since day one and said nothing, because until about six days ago there wasn't enough of it to be sure and the thing doesn't guess."

"And six days ago?"

"Six days ago the number got big enough to bite." His finger went to the low end of the plot, the sessions sitting down around seventy-eight. "That's you alone. Every time. Seventy-eight three. Seventy-nine flat. Seventy-seven six. Best you ever managed with the hangar empty was eighty point one and you were sick in the wash trap after."

"I remember."

"You would." The finger moved left. "That's you with her on the gantry. Eighty-eight. That's you with her on the floor at eleven metres. Ninety-two. That's the cold start on day one twenty-six —"

He did not finish. There was no need. Everyone in the room had been present for day one hundred and twenty-six, and two of them had been carried out of it.

"Ninety-nine point four," said Leon.

"Ninety-nine point four." Garren drank, finally. One measure. Set the mug down square. "For eleven seconds. On a frame the spec caps at design authority, which is a hundred, which is a number your father put in because he thought it was a wall."

"It didn't strain anything."

"That's my point. Peak actuator load across the whole hip group was sixty-one percent of rated. Coolant delta-T came up four kelvin and came back down. The drives were inside their envelope the entire time." He turned the mug a quarter turn. "That's not a machine performing well. A machine performing well makes noise. That's a machine being handed something."

Eliana had not spoken. Leon could see her at the edge of the pane's glow, sitting straight on the bench with the stick across her knees like a bar, the concentrator bead going on and off at her hip.

"Run the pilot term out," Leon said. "Set my sync to zero. See what's left."

VEDA did it in under a second, which was the answer.

MODEL FIT WITHOUT PILOT TERM: r = 0.91. MODEL FIT WITHOUT PROXIMAL MASS TERM: r = 0.29.

"There it is," said Garren.

"That's not right," Leon said.

It was the most honest sentence he said that day. He had said it to himself at three in the morning on the ninth day with a file open and his hand over his mouth. He was simply not saying it about the same thing.

"It's right," Garren said. "It's just not what any of us signed for."

Garren Doss had eleven years of reading Aria Zadkiel's telemetry and had never once claimed to be a physicist. He got to the middle of things by a route no physicist would have recognised: what is this machine actually doing, and who is paying for it.

He took about ninety seconds.

He did not get to a standing coherent harmonic in a living cellular lattice. He did not get to twenty years of characterisation filed under a letter that had never been expanded, or to why a neural coupling lattice needed the mathematics of a body that rings.

He got somewhere with a shorter road to it.

"It's not that she helps it." He was looking at the frame, not the pane. "Anyone can help a machine. Put a better cooler on it, it runs cooler. That's helping." He turned the mug again. "This is that it doesn't work without her. Seventy-eight isn't a fighting number. Eighty-five is the floor for full authority — your father wrote that, not me. You're seventy-eight alone and ninety-two with her stood on the floor. So it isn't a frame with a pilot in it. It's a frame with two seats and only one of them's got a chair."

"That's a lot of conclusion off one plot," Leon said, because that was what a man seeing the plot for the first time would say.

"It's one plot with fourteen hundred points in it." He coughed and rode it out with his hand flat on the desk. "Year six I read a plot that said your father's left-hand loop would gall at four thousand hours. Everyone told me I had one graph and a bad attitude. It galled at three thousand nine hundred and forty."

Quiet. Up through twelve metres of rock, faint, the compressor whined at thirty-one percent.

"I'll say the practical thing," Garren said, "and then I'd take it kindly if nobody made me say it twice."

"Garren —"

"If that machine only makes fighting numbers with your sister inside nine metres of it, then the Reach doesn't need a pilot. It needs a pilot and it needs her in the hangar. Then it needs her on the gantry. Then it needs her in the cockpit, and after that it doesn't need you much at all." He looked at the deck. "That's what a war does with a fact like this. That's the whole of what a war is. It finds out what makes the machine work and it goes and gets it."

He stopped.

"That was a filthy thing to say in front of her," he said. "I'm not going to pretend I didn't say it and I'm not going to dress it. I'd like the record to show I know what it was."

"It's all right, Garren," said Eliana.

"It isn't."

"No." She shifted her hand on the stick. "But you're the only person in this room who's ever given me a number without checking my face first. I'd rather have you filthy than careful."

Leon kept his hands still on his knees.

That was for me. She didn't even look at me and it was for me.

Eliana got up.

Neither of them offered. Offering was the last thing that could still make her properly angry, and there was something almost restful in watching her refuse help nobody had extended. The stick went down. Her left hand went white on the strapping. She came off the bench in two movements with a pause between them, and the pause was five seconds long, and Leon counted it and could not stop counting it.

She got four metres out onto the hangar floor. Then she stopped and looked up.

"I felt it," she said.

"Felt what, love," said Garren.

"On day one hundred and twenty-six. When it went to ninety-nine." She was breathing off the top of her lungs. The line hissed. "Four days of everybody asking me very carefully what I remember. Nobody has asked me what I felt. I remember all of it. I have been lying up there waiting for one of you to ask a question that wasn't about my saturation."

"Ellie —"

"Let me get it out in one go. I haven't got two goes in me."

He shut his mouth.

"It didn't start on day one twenty-six," she said. "It started on the nineteenth day."

Day nine. Day nineteen. Ten days between them. Ten days in which he had already sealed a file and she had not yet begun keeping a secret.

"The lights," she said. "On its collar. The amber ones in the standby line. They follow me."

Garren said nothing at all.

"They aren't supposed to have a behaviour. They're a heater indicator. Garren told me himself in week two — thirty-one points, four hundred watts, keeps the lattice from setting." She adjusted her weight and the strapping creaked. "They track me across the floor. There's a lag, about half a second, and it's longer when I'm tired. I stand still, they stop. I go left, they go left. I go behind the cradle where there's twelve metres of rock between us and they still go."

"How do you know," said Garren.

"I tested it eleven times. Once with my eyes shut, with Pip reading them out to me, so it wasn't me doing it and calling it evidence."

"And Pip," said Leon, because he was supposed to be finding this out.

"Pip fails inside nine metres." She said it like a maintenance note. "Not instantly. About forty seconds of margin, then the ducted fans go asymmetric and it starts to yaw, then the telemetry drops out, then the distress call. Three up, pause, three up. It did that every time until week nine. Then it stopped doing it." A breath. "I think it stopped because its cells are going and it hasn't got the power to complain any more. That's worse."

"Nine metres," Garren said.

"Nine. Not eight, not ten. It's a hard edge. I stepped it out with a tape."

"You stepped it out with a tape."

"Four times. It's nine."

"Why didn't you tell us," Leon said.

He asked because he had to ask. He asked knowing the answer, and knowing that his own answer to the same question was worse, and he heard his voice come out level and warm and exactly like a brother's.

"I'm getting to that."

She turned around. She had to do it in stages, one hand crossing to the stick and back.

When she was facing them she was smiling, and that was when Leon understood that the next thing would be worse than anything on the pane.

"When I touch it," Eliana said, "I'm well."

Nobody moved.

"I don't mean better." Still smiling. Not the smile she used on doctors — the one with the small hard edge that meant give me the number and go. This one was open. He had not seen it since a garden, when she was twenty and could still walk to the wall and back. "Better is what Tessamine does. Better is the pain going down two points and an hour of sitting up, and you're still inside it. Same room, bit more air in it. Better and I are old friends."

"Ellie."

"This isn't that. Hand flat on the inner lattice, on the open shoulder block — the armour does nothing, it has to be the lattice — and I am well."

She lifted her free hand and looked at it while she spoke, the way you look at something you have been handed.

"My hands are warm. There's no stop in my chest. There is a place two-thirds of the way down a breath where my chest says no, and I have had it since I was eleven, and I stopped noticing it the way you stop noticing a floorboard. It isn't there." She turned the hand over. "Nothing hurts. Not my hip. Not my back. My jaw has hurt for six years and I've never told anybody, because who tells somebody their jaw hurts. It stops. Not fading. Off."

The compressor whined.

"And I'm strong," she said. "I could take the observatory stairs two at a time and not be short at the top. Not think. Know."

She lowered the hand.

"It lasts exactly as long as I'm touching it. The second my hand comes off it's over, and there's no taper. Then, about forty seconds after, I bleed. Nose first, both sides, six or seven minutes. Twice it's been the ears as well." She shrugged one shoulder. "I don't know the mechanism and I'm not pretending to."

"How many times," said Garren. His voice had gone very flat.

"Forty-one."

"Forty-one."

"Since the nineteenth day. Twice some weeks. None at all when you two were down here at night." She was calm. That was the unbearable part. She was calm and she was pleased. "And before either of you says it — yes. It was a stupid secret and I know precisely how stupid. I kept it because the day I told you would be the day it stopped."

Leon said nothing.

"I have been ill since I was nine," Eliana said. "I have never had one hour of not being ill. I got forty-one of them. I wanted them and I took them."

She asked the question the way she asked everything, straight down the middle with no run-up.

"So. What does it do to me?"

He had been ready for it for a hundred and twenty-two days.

He knew the mechanism. He knew what the letter stood for; he had worked that out in about a second and had wished, briefly, to be stupider. He knew that both frames were tuned to it. He knew that 61.4 was not talent and 91.7 was not talent and that she had no figure at all because she was not a rating.

He knew the doubling time. Forty-two seconds.

He knew the lifetime total. Cumulative, not per sortie. Under nineteen minutes.

He had already spent eleven of them.

"It's a resonance problem," Leon said.

He said it slowly. He did not say it too well — a man telling the truth about something difficult stumbles once, near the start, and he put the stumble at the end of the first clause where it would do the most work.

"Your lattice runs at a fixed frequency. That's what Verrine decay is — it isn't degenerative in the ordinary sense, there's no agent, nothing is eating you. Your cellular structure holds a standing oscillation, and matter doesn't stay bonded at that frequency, so you come apart at the rate of the oscillation. Orr knows this. Everyone's known it since you were nine. What nobody's ever had is a way to interfere with it."

"And that thing interferes with it."

"That thing cancels it. Locally."

He turned to the pane and let VEDA draw two sine curves, because it made the thing look like it had come from somewhere other than his mouth.

"The Psycho-Frame carrier sits at eleven point four kilohertz. Yours is a harmonic of it — close enough that in contact the lattice phase-locks to you and runs the inverse. Destructive interference. While you're touching it, the oscillation is flattened, and everything the oscillation was doing to you stops. That's why it isn't better. It's not treating a symptom. It's switching off the source for as long as the contact holds."

She was listening with her whole face.

"The cost is real, and the cost is the bleeding," he said. "The frame can't build a cancelling waveform out of nothing. It has to draw the phase reference from you. So for those minutes it's taking structural coherence out of your lattice to make the thing that's protecting your lattice. You're paying for the shield with the wall. Capillary failure, mucosa first — that's the nose — and the round window in the ear if it runs long. It's a debt."

"How big a debt."

"About four tenths of a percent of cumulative structural integrity per exposure, at the contact levels you've been running."

He said it cleanly. It had the exact texture of a figure that has been measured.

"And it's recoverable. That's the part that matters and it's why I'm not throwing you out of this hangar. The curve is logarithmic, not linear. It flattens. The first thirty seconds of contact cost nearly all of it and everything after that is nearly free — which is why forty-one exposures haven't killed you, and why eleven seconds on day one twenty-six cost you a kilogram and a half and not all of it. It doesn't stack. It re-phases out over about eleven days."

"So four days in bed —"

"Are four days of eleven. You'll get the weight back. Not all of it. Most."

"And in the cockpit?"

There. He did not pause. The pause would have been the tell.

"In the cockpit you'd be a passive element," Leon said. "You can't couple. You've no sync figure at all — I've run you against the curve four times and there's nothing there. It isn't low. The axis doesn't apply to you. You're not a nervous system the frame can read. You're a dielectric. You perturb the field by being in it and the frame gets a better field, and that is the entire content of the ninety-two on that pane and the entire content of the point nine four."

He held her eyes, because a man telling the truth looks at you.

"It's proximity. That's all it is. You are not driving it, you cannot drive it, and there is no path for it to take more from you than the contact debt. Not a small path. No path. There is no mechanism. There's just a number that gets better when you're stood nearby."

He let a beat go.

"It's the best news in this room," he said. "The machine works better with you in it, and for six minutes at a time it makes you well. I've spent four days looking for the trap and there isn't one. There's a bill. The bill is small and the bill gets paid."

Then he reached over and straightened the fold of her cardigan where the stick had rucked it up at her hip.

She did not answer for a long time.

The compressor whined. Up in the cradle, thirty-one amber points held their attention on a small woman four metres out on the floor, half a second behind her.

"You straightened my cardigan," Eliana said.

"It was —"

"Mother used to do the pillow." No edge on it at all. "Orr does the chart. She hangs it and then squares it on the hook. Kessler at the dispensary moved my glass about two centimetres, every time, for two years. All of them. They find something of mine, they put it right, and then they open their mouths."

Leon's hand was still half out. He brought it back and set it on his knee.

"You have never done it," she said. "In your entire life. You are the only person I have ever known who talks to me with his hands still."

He said nothing. Nothing in a hundred and twenty-two days of preparation covered it.

She held his eyes. He counted. Four seconds. Five.

She had all of it except the content. She had the fact, the shape of the fact, the weight of it, the date it started. She did not have a line of what was in the file and she was never going to get it out of his face. Both of those were true at once, and she knew both of them too.

Then she let him have it.

He watched her do it. That was the part he would carry: she did not sigh, or soften, or look away first. She made the decision visibly, the way you watch somebody set down a stone.

"All right," Eliana said.

"All right?"

"All right." She got the stick properly under her. "Four tenths of a percent and eleven days. I can work with that. Tell Garren to put that strap where I can't see it and I'll come down every day and stand in the ring and make your machine embarrassing."

She turned for the door. Stopped. Said something in Old Astraian.

Six words. Low, unhurried, in the accent she had from their mother and he had never had, because Elizabeth had taught her and had not taught him, and it had been a joke in that house for twenty years — your brother sounds like a customs officer, don't let him try.

He caught one root. Veres-.

He knew that one. It lived in the phrase their mother used at the end of arguments. I see it. I know what this is. The one she had used on their father in the kitchen at four in the morning when he came home with a number in his pocket and a story about the lab.

"What's that mean?" Leon said.

"It means thank you," said Eliana.

It did not. He knew the word for thank you. It was one of the six he had, and their mother had made him say it to the gardener every week for a year, and it had no v in it anywhere.

"Ah," he said.

"Yes."

She went. It took a long time. She did all of it herself and he stood and let her, and understood, with nothing in it that resembled comfort, that he had just been handed exactly what he had been handed on a staircase on Veridus-9 sixteen months ago. That she had handed it to him deliberately. That they were now two people in a room who had agreed to let each other lie, and that neither of them would ever raise it again.

Garren found him at the fabrication cell an hour later. The feed hopper was down to eleven percent and wanted eleven hundred kilos, and Leon had been standing in front of the gate for four minutes doing nothing whatsoever.

"Logarithmic," Garren said.

"Mm."

"You had a lot of that very ready."

"I've had four days."

"You've had four days." Garren leaned on the cell frame and coughed and did not apologise for it. "I did eleven years of your father's telemetry. I'm not a clever man and I've never once pretended to be. But I know the look of a graph that comes out of a pocket instead of off a screen." He waited. "How long have you known?"

Leon opened the hopper gate and started the charge cycle. The feedstock went down the throat with a noise like rain on a roof.

He did not answer. He let the noise be the answer, and let the seconds go by — four, six — and Garren watched him not answer and did not ask again, because Garren Doss had never explained himself to anybody and did not expect it in return.

"Right," Garren said.

"Right."

The old man drank his second measure and put the cup down. He was quiet long enough that Leon thought it was finished.

"I'll say one thing and then I'll leave off." His voice had gone gentler than Leon had ever heard it, which was worse than the cough. "Your father would have done this alone. All of it. Sat in that chair with the whole of it in his head and told nobody. Not me. Not your mother. Worked it and worked it until it killed him, and it did kill him, and half of that was the work and the other half was the not telling. Eleven years, and there was never one night I could have got in there with him."

He put his hand on Leon's shoulder. Two seconds. He was not a man who touched people.

"You're not him," Garren said. "Whatever's on you, you've got her and you've got me. You've never carried anything alone in your life and you're not starting now. That's the whole difference between the two of you. Get some sleep."

He went out. His boots went off up the corridor and the cough went with him.

Then there was only the hopper, and the rain-on-a-roof noise of eleven hundred kilograms of feedstock going down into a machine that was ninety-six percent finished.

Leon stood there and let him have it.

Thank you, he thought, in the only language he had.

The fabrication cell finished the last eight percent at 04:12 on the hundred and sixty-first day and did not mark it. No chime. No status flag. The extrusion head withdrew nine centimetres, parked, and stopped drawing current. The feedstock hopper read 0.4 percent and held there. The line that had said BUILDING for a hundred and sixty-one days said IDLE.

Leon was asleep on the gantry with his coat under his head. He woke because the noise stopped.

He lay in the absence and counted it — eleven seconds, he counted everything now, it happened without him — and then sat up and looked at the thing in the cradle.

Twenty metres. Head down, service umbilicals still hanging off the shoulder ports. Gundarium Epsilon under an uncured nano-laminate, matte, the colour of wet ash. It did not look like a weapon. It looked like a very large tool somebody had left in a room.

Eight percent, he thought. Twelve days of that was pipe.

He went down the ladder and started the checklist.

The funnel control lattice took four days. He had budgeted six. It was the first estimate in five months to come in early, and he did not trust it.

Six heavy GN fin funnels. Two point four metres, three hundred and eighty kilos dry, each with a micro-condenser rated to eleven seconds of continuous discharge and forty-one seconds of refill off the dorsal bus. That part was arithmetic. The hard part was phase.

All six had to hold phase with the frame and with each other, and GN field drift is not forgiving. Two funnels four degrees out of alignment do not miss. They interfere, and the interference node is a shell of unstable field about nine metres across that will take an arm off whatever generated it.

His father's tolerance was 0.15 degrees. Leon calibrated to 0.04, because he had the time, and because the number had been left to him by a man who had died of his own machine.

He ran it cold on the hangar floor, funnels racked, cycling each emitter against a reference plate. Singles first. Then pairs. Then the full six-body solution, which failed nine times in a row on the cross-term.

The tenth held four minutes and drifted 0.31 degrees on funnel four.

He pulled funnel four. Stripped it on the bench under a work light with his hands inside a unit that could unmake him, and found a condenser sleeve seated eight-tenths of a millimetre proud. The cell had drawn it at 0.2 degrees warmer than its five siblings. Two tenths. Eight tenths of a millimetre. A dead arm.

He reprinted the sleeve. Thirty-one hours.

The coolant runs he did by hand, because the cell could not weld inside a closed torso and he would not have let it.

Primary loop, helium-phase, six hundred and twenty litres at forty-one bar, up through the spine truss and out to the shoulder radiators. His father had specified single-length draw for every run above thirty bar. No couplings, no joints, nothing in the heat path that had ever been two pieces.

The log entry attached to the specification was four lines long and Leon had it by heart.

Single-length draw above thirty bar. If the run will not go in one piece, make the run shorter. There is no acceptable weld here. I have tried nine.

Leon understood the first time he read a pressure trace at full authority. A weld in that loop would hold about nine minutes of hard flight. Then it would open, and six hundred and twenty litres of helium at forty-one bar inside a sealed torso would make a pressure vessel out of the cradle, with a man in it.

He threaded the lines through the truss like sewing rope through a needle. Nine days. His hands shook for the last three, so he worked slower, so it took a tenth, and that was that.

The buster rifle capacitor trees came out of the cell in four sections. He assembled them on the bench: ninety-six cells to a tree, four trees, cross-linked through a common bus behind a hard mechanical disconnect — a physical bar, thrown by a physical solenoid, because the failure mode of a bank that can dump into a hyper-mega array is not it does not fire.

The failure mode is it fires.

Charge from the photon battery: 3.9 seconds. One discharge took the battery from full to eleven percent. Recharge at rest off the twin drives, one hundred and forty seconds. In flight, under manoeuvre load, closer to four minutes.

Two shots, he thought, and then I am a very expensive knife.

The cleaver mag-lock was a morning's work and the dullest system in the machine, which was why he built it twice. Dorsal mount. Three point one tonnes of high-frequency blade hanging off a lock rated to sixty g of shear. He took it to seventy-two with a jack and a strain gauge and it held.

Then he stripped it and rebuilt it from new stock, because a lock that has been walked to its margin once is a lock that has been used.

That left the Moonlight Butterfly.

Eighteen canisters. Sixty-two kilos each. Nano-chaff, a shaped dispersal charge, a tuned EMP initiator, racked low in the back in two banks of nine on a rail that dropped them clear in 0.4 seconds. Effective radius, a hundred and forty kilometres. On the specification sheet, in his father's hand, underlined once: no discrimination.

Garren came down the ladder while Leon was staging the first canister on the lift.

He stood with his hands in his coat pockets and his breath moving in and out of him in that wet patient way, thirty years of lattice dust doing its slow work, and he looked at the racks a long time.

"No."

"I need a second pair of hands on the seating collar. It's a two-man collar."

"I spent thirty-one years cutting people out of collapsed lattice with a rescue frame," Garren said. "That kills every frame that would come for them."

He went back up the ladder.

Leon loaded eighteen canisters alone. Nine hours. He tore something in the left shoulder on the fourteenth — a hot wire from the joint down into the bicep, and then nothing, which was worse — and finished the last four one-handed with the chain hoist doing the work and his boot on the rail to keep it true.

When the eighteenth seated he sat down on the deck plate and laughed once at nothing, because his shoulder hurt and there was nobody to tell.

At 21:40 on the hundred and seventy-fourth day, the readiness board went green across all systems and the completion line read 100.0.

He stood under the sole of its right foot, four metres above his head, and looked up.

You're finished, he thought. I'm not.

He took it to full authority four days later, alone, in the dead zone after the picket cleared.

The habitat was two hundred metres up and behind eleven metres of regolith and Eliana was asleep in it, which he had checked twice. Garren was in the observatory shell with the passive array and a flask he had not opened. That was the audience. A dying woman who did not know, and an old man who would not watch.

Coupling initiated 06:02.

The Psycho-Frame does not feel like putting something on. It feels like a room going quiet. All his life there had been eighty milliseconds between wanting and doing — the civilian Halo Link, governed, safe, eighty milliseconds slow, which had cost eleven million people ninety minutes. Eighty milliseconds is the width of a blink. It is also the difference between a hand and a hand you are watching on a delay.

The frame took the delay out.

Sync climbed the way it always did. Forty. Sixty-one. Seventy-four. It held at 81.0 while the lattice found the shape of him, the way a coat finds a shoulder, and then went to 89.4 and sat.

Ceiling 91.7. His father's had been 61.4.

Six points of headroom with the throttle open.

"VEDA. Authority to one hundred percent. No governor."

Acknowledged. Structural margin at one hundred percent is fourteen point two percent. Thermal margin is nine. Both figures assume the coolant loop is as clean as you built it.

"It is."

Understood is not the same as accepted, Leon.

"Accepted."

The twin drives came up inside a second of each other and the deck plate went from cold to warm through his boots. Cradle clamps released at four points. Twenty metres of Gundarium Epsilon walked out of the vault door on its own feet, and Meridian-7's thin morning came in around it, rust and bone, no wind worth the name.

He went up.

Slowly. That was the first thing he had learned and the only one that had cost him blood: the machine wanted to be fast, and being fast was not the skill. He climbed at eleven metres a second with his hands at his sides and let the airframe settle into 0.4 bar of nothing much to push against, watching load traces come green in the order he had rehearsed. At four thousand metres he opened the wings.

The overcharged Minovsky drive threw them out of the shoulder vanes as two flat sheets of light. Curved, silent, eleven hundred and eighty metres a side at half span.

He took them to full.

Fourteen hundred metres each. Two point eight kilometres of wing on a twenty-metre body. From the ground it would have been a white line across a third of the sky.

There was nobody on the ground.

They were not decoration. The leading edge of each wing was a confined field boundary four hundred nanometres thick, and it did not cut so much as decline to permit two things to go on being adjacent. He had learned that on day sixty-one, clipping a ridge at half span and taking two hundred metres off the top of it, and had spent that night with his nose packed and his left hand unable to hold a spoon.

Now he flew them. Level line, four thousand metres, ninety seconds, hands still.

That was the exercise. Full span redistributed the mass of the entire machine, and the frame wanted to trim it, and the trim was a lie — the frame guessing what he meant. Let it guess and it guesses again, larger, and somewhere past 91.7 the guesses stop being guesses and start being instructions.

So he did nothing. The machine did nothing. After ninety seconds it stopped offering.

There it is, he thought. Don't want anything you haven't already decided to want.

"VEDA. Slingshot. Marker one, then the shelf."

Field forming. Nine point one seconds to release. Battery at ninety-six percent.

The slingshot is badly named. Nothing is thrown. The field closes an inertial volume ahead of the frame and then collapses it, and the frame falls into the collapse, and it does that forty-one times a second. The acceleration is obscene and almost none of it reaches the cradle.

Almost.

Station-keeping to 0.041 c in nine point one seconds. The spine truss logged a peak structural load of forty-one thousand g. Three point one reached him.

Three point one g is a shove. A healthy man takes it for a minute and complains after. What it is not is any honest account of what has just happened to you, and that gap was the most frightening property of the machine — the body's alarm had been unplugged from the event. His body believed it had been shoved. The truss believed it had been fired out of a rail. Both were correct.

Meridian-7 is nine thousand four hundred kilometres across.

He crossed it in seventy-seven hundredths of a second.

Then the difficult part, which was stopping.

Deceleration is not symmetric. The collapse field pulls; it does not push. To shed velocity you invert it, and inverting it while carrying two point eight kilometres of wing is reversing a sail in a gale that does not exist. Day ninety-four he had put himself three hundred kilometres past the mark with a fourteen percent thermal overrun and forty minutes of nosebleed.

Today: furl at eleven hundred kilometres, invert at four hundred, shed in a flat arc that finished one kilometre over the Sirrah Shelf.

Overshoot, sixty-two metres.

He hung there. Radiators dumped. The frame ticked around him like a stove cooling.

"Sixty-two," he said, to nobody. "Sloppy."

Mean overshoot across your last eleven runs is one hundred and nine metres. This is your best.

"Sixty-two is still sixty-two."

Then he killed the rocks.

He had spent a week setting them. Forty-one basalt spires and blocks over ninety square kilometres, none under nine metres, arranged in no pattern at all, because a pattern is a kindness. Fourteen were bolted to old survey rail sleds and ran random walks up to eighty kilometres an hour. Nine carried chaff dispensers off the Dray's fire suppression stock. Four carried jammers.

He launched the funnels.

Six out of the dorsal racks, and then the thing that had cost him four days of calibration and would have killed his father: they went where he looked. Not quickly. There was no interval. They were not units he directed. They were a way of being in six places, and the six places had his attention in them the way his hand has his attention in it.

He built the killbox and moved it. Three high, three low, converging cone, the whole geometry rotating around the field at a hundred and forty metres a second so that no spire sat inside the same solid angle twice. Discharge. Translate. Discharge.

Thirty-one spires in nineteen seconds.

The jammers he took with the frame's own beam ports, because jamming does nothing to a man who is not using a radio.

The movers were the interesting ones. He let them run. Two full minutes, sleds crossing and recrossing, chaff up, and he flew the funnels through the chaff and did not fire — waiting, letting the sleds acquire the confidence of a thing that is not being shot at — and then closed all six condensers inside a two-second window.

There were no sleds.

Forty-one of forty-one, VEDA said. Elapsed two minutes forty-one. No friendly-line intersections. Maximum phase excursion zero point zero six degrees on funnel two. Thermal margin four point one percent and holding.

"Four point one."

Holding.

He was breathing hard. His mouth tasted of coins.

"Mesa."

Four kilometres east. Three hundred and ten metres tall, a kilometre and a half on the long axis, four hundred million tonnes of layered iron-red sediment standing exactly as it had stood through every day of a world with no weather to take it down.

He drew the cleaver off the dorsal lock. Three point one tonnes, edge running high enough to make even 0.4 bar of air hiss along it, and came in level at two hundred metres and nine hundred metres a second.

He did not swing. That was the amateur's instinct, and at nine hundred metres a second the arm is a passenger. He locked the blade rigid at forty-one degrees off the flight line, let the airframe be the swing, and went through.

Forty-one metres deep. Fourteen hundred long. He was past before the sound got there.

Behind him, over about eleven seconds, the top of the mesa slid off.

He did not watch it. He was already turning.

And the whole time — funnels, killbox, mesa — the Zero System was quiet.

That was the actual test. That was what five months had bought.

Zero is not prophecy. It is a probability engine running at Psycho-Frame bandwidth, which means it does not tell you the future; it shows you all the branches at once, weighted, faster than the part of you that decides. Day nine it had shown him fourteen hundred branches of a single funnel launch and he had come out of the cradle with his ears ringing and no memory of the previous eleven seconds. Day thirty-one it had shown him his sister's death in nine variants, inside a firing solution, unasked, as ordinary weighted futures — because that is what they were — and he had been sick in the cradle and told Garren it was a coolant leak.

You do not switch Zero off. You prune.

He had learned to cut branches before they finished forming. Not by wanting less. By deciding earlier. Fourteen hundred to sixty to nine, and today, across two minutes and forty-one seconds and four hundred million tonnes of rock, it had offered him four. He took one. It did not argue.

It was quiet because it had finished learning what he was.

He climbed to twelve thousand, opened to full span one more time, and flew a single line west along the dead terminator with the tip of the port wing two metres under the regolith.

Eleven kilometres of trench. Four metres wide. Straight to within the width of a hand.

Then he furled, and turned, and went home, and the only witness was a world that had been dead before anyone thought to name it.

Post-flight took ninety minutes. The honest part took four.

He sat in the open cradle with the frame ticking and read the medical block the way you read any log, because that is what it was.

Mass 71.4 kilos, down from eighty-four. He had stopped being hungry in month two.

Epistaxis after every session above seventy percent authority. This was the sixty-first. Nine minutes today, which was good. Worst was fifty-one.

Left-hand intention tremor, onset around forty-one percent authority, resolving in about forty minutes post-decoupling. Resolving to a baseline that was not month one's baseline. There was a curve in that and he had fitted it once and did not look at the fit any more.

A four-kilohertz notch in the right ear. Permanent. He had run the audiogram himself eleven times with a hand terminal and a tone generator to be sure of the shape.

Sleep, three hours forty. The sleep was not his. He dreamt in telemetry — load traces, phase drift, the exact colour of a thermal margin at nine percent — and four days ago had woken on the gantry having solved a coolant routing problem correctly while unconscious.

Two syncope events. 88.1 coupling on day one hundred and two, fourteen seconds. 89.0 on day one hundred and thirty, six seconds. Neither logged anywhere Garren could reach.

Fingertip thermal discrimination below fifteen degrees: absent. He had established this by picking up a chilled coolant line and noticing nothing.

The involuntary arithmetic was worse. He counted stairs, breaths, the fan revolutions of his sister's drone, the perforations in the deck plate between the cradle and the ladder — four hundred and eleven — every crossing, every time.

And the item that was not on the block, which he added himself, in silence, at the bottom of the ladder before he went up: she is dying, she is twenty-three, be her brother. It did not arrive on its own any more. He mounted it. Some days the seam showed. Some days she saw the seam and let it pass, which was worse.

He wiped his face with the heel of his hand.

His father had flown at 61.4 and had thirty-nine minutes in him. In those thirty-nine minutes he unmade eight hundred and seventy warships. Then he stopped being a man.

Leon had six points of headroom above 89.4 and no idea what was up there, because nobody had ever been.

The difference between the two numbers was not talent.

It was two hundred metres over his head, asleep, on a supplemental line, at twenty-nine point one kilos.

He did not say it out loud. He had not said it out loud in ninety-eight days.

He closed the log and went and cleaned the funnel racks.

The signal came in on the passive array at 03:51 and Garren woke him with a hand on the good shoulder, which meant it was bad, because Garren did not touch people.

"Concord civil band. Channel four."

"Nobody's used four in eighteen months."

"Because the Dominion listens to it." His breath went in and out. "Come up."

The observatory shell was cold enough that their breath hung in it. The array was Garren's five months: nine metres of scavenged dish, a cryo pre-amp built out of the Dray's spare refrigeration plant, a spine of cable clipped to the ruin of the old dome. It could not transmit. That was the design.

The loop had been running eleven hours before the dish caught it. Garren had the intercepts stacked in order and let them play.

CONCORD CIVIL EMERGENCY BAND, CHANNEL FOUR. THIS IS MARDA KELL. WE ARE AT THE OLD PUMPHOUSE, KESSLER FLATS, HOLLOWAY, GRID FOUR-ONE-NINE. THERE ARE NINETEEN OF US. NINE ARE CHILDREN. WE ARE NOT COMBATANTS. WE HAVE WATER FOR SIX DAYS. IF YOU CAN HEAR THIS PLEASE COME.

Ninety minutes. Same voice. Same script.

...THERE ARE SEVENTEEN OF US. NINE ARE CHILDREN...

Then the same. Then the same again. Water for six days, unchanged, three times, while the first number moved.

...THERE ARE FOURTEEN OF US. SEVEN ARE CHILDREN...

Then once, the wrong way:

...THERE ARE FIFTEEN OF US. SEVEN ARE CHILDREN...

Somebody had come across the flats in the dark and been let in. She had gone back to the set and put the number up.

Two more at fifteen. Then:

...THERE ARE NINE OF US...

Then the voice changed. Younger. Reading it the way you read a page handed to you, stopping in the wrong places, except for Kessler, which he said like a place he had lived.

CONCORD CIVIL EMERGENCY BAND, CHANNEL FOUR. THIS IS ANSEL KELL. WE ARE AT THE OLD PUMPHOUSE, KESSLER FLATS, HOLLOWAY, GRID FOUR-ONE-NINE. THERE ARE SIX OF US. TWO ARE CHILDREN. WE ARE NOT COMBATANTS. WE HAVE WATER FOR SIX DAYS. IF YOU CAN HEAR THIS PLEASE COME.

The last one on the stack was forty minutes old.

...THERE ARE SIX OF US. TWO ARE CHILDREN...

Unchanged. Which meant nothing had happened in forty minutes, or the person keeping the number right had stopped.

Leon listened to the stack twice through. Garren let him.

"Pacification sweep," Garren said. "They don't rush those. Work a grid, take a building a day. They leave the band open on purpose — saves them walking."

"How long for six."

"Two days. Three if the officer's lazy."

"Distance."

Garren looked at him. "Leon."

"Distance, Garren."

"Eleven light years and a picket."

He laid the course on the vault terminal with the loop still running in the corner of the display, because he did not turn it off.

"VEDA. Holloway. Kessler Flats, grid four-one-nine. Work me a departure inside the picket window."

The Meridian picket cleared local space nineteen hours ago on the thirty-one day cycle. Your uninterrupted window is two hundred and forty-four hours. Transit at continuous cruise is one hundred and nine. You will arrive with twenty-six hours of operational margin before a return departure becomes marginal.

"Then it's marginal."

Then it is marginal.

Pre-flight. Feedstock into the micro-repair lattice hoppers, both banks to full — the lattice would weld a fracture and would not regrow a limb, and he had read that sentence of his father's until it stopped meaning anything. Photon battery to full and held on trickle. Funnel condensers cycled twice, discharge into the ground plate, forty-one seconds each. Coolant topped to six hundred and twenty litres exactly and pressure-checked at forty-four for eleven minutes.

Cleaver mag-lock stripped and rebuilt a third time, because he had hands and time and nothing else to do with either.

Garren stood at the bottom of the gantry with the flask unopened. He had taken his two measures at nineteen hundred and stopped, the way he did.

"Say it," Leon said, without turning.

"One machine. What do you think one machine does?"

Leon set the torque driver on the rail. Wiped his hands on a rag that had stopped being any use in month three.

"From the traffic we've pulled, the Dominion has about four thousand one hundred hulls of the line and something over nine hundred thousand people in occupation garrisons across the Reach," he said. "I can't fight that. I'm not going to. That isn't the arithmetic."

"So what is."

"A sweep on Holloway is one company, one lift ship, probably two escorts. Four hundred people, four hulls. If I go and take them away, the Reach has four thousand and ninety-six hulls in it instead of four thousand one hundred, and Kessler Flats has six people in it instead of none."

He picked the driver back up.

"I'm not going to win. I'm going to subtract. Then I'll do it again next month, and the month after. Eleven years of that and I've moved the third significant figure."

Garren was quiet a while. The drives ticked over on standby behind them.

"Your father asked me a question once."

"Don't."

"He'd worked the numbers on the Ring defence grid," Garren said, as though nobody had spoken. "Sat me down at a table and walked me through it, line by line, the way he did. Said he couldn't hold it. Said he'd take what he could off the top and hand the rest to whoever came next." A pause. "Same face you've got on now. Same flat voice. Used the same word."

"Which word."

"Subtract."

Leon torqued the last fastener to forty-one newton metres. "Then it's a good word."

"It's the word of a man who's already worked out he isn't going to be standing there for the third significant figure," Garren said, and went up the ladder.

She was awake when he came into the habitat. The concentrator ran at a different note when she was breathing hard and it had been at that note for an hour.

Four blankets on the bunk and she was inside all four with her knees up and the cardigan over everything, because she would not be seen without it. Pip sat on the shelf above her head, fans still, indicator dimmed almost out so as not to be a bright thing in a dark room.

"You're going."

"I'm going."

"How long."

"Nine days if it goes correctly."

"And if it doesn't?"

"Then a different number."

She looked at him. Pale violet in the low light, ordinary, which meant she had decided not to be frightened yet, which was not the same as not being frightened.

"Bring me a coat," she said.

He laughed before he could stop it. "I'm going to a pacification sweep."

"Sweeps happen in towns. Towns have shops." One arm came out of the blankets. She put her thumb through the hole in the left elbow and wiggled it at him, the way she had for two years. "Wool. Sized. Actually sized, Leon, not sized the way you size things, which is 'that'll do' and then it doesn't do."

"You had one job on Veridus and you chose that jumper yourself—"

"I chose it because it was four marks and you had eleven." The thumb kept going. "Wool. Buttons that work. No hole."

"You don't want the hole mended? You've had that hole longer than you had the pearl brush."

"Don't you dare mend it," she said. "It's load-bearing."

He sat down on the deck by the bunk, because standing had stopped being free.

"And when I bring you a coat that fits."

"Then," she said, with enormous dignity, from inside four blankets at twenty-nine kilos, "we will consider treating you like an adult."

"That's not how the joke goes."

"It's my joke. I've had it eleven years, I'm allowed to turn it round." The thumb dropped. "You're twenty-six, you sleep on a gantry, you eat one meal in two days, and you think I don't count them."

"You don't."

"I count everything. It's a family disease."

"It's not the family disease."

"No," she agreed. "That one's mine."

Pip's fans spun a half turn and settled. The concentrator changed note. She waited for her breath to come back and did not remark on the wait, and neither did he, because remarking on it had been ruled out by treaty about a year ago.

Then she said four words in Old Astraian, low, the vowels going somewhere his mouth had never been.

He tried them back.

She winced with her entire face. "No. Oh, that's foul. Leon, that is genuinely worse than last time. Mother would have had to sit down."

"Mother taught you that on purpose."

"Mother taught me that on purpose," she said, comfortably, "because you were seven and unbearable and she wanted one room you couldn't get into."

He laughed. She laughed, and then had to stop, and lay getting her air back while the machine on the shelf watched her with its light turned down.

The room went quiet the way rooms did now, without anyone deciding to.

"Ask me," he said.

"I'm not going to ask you to come back."

"I know."

"You'd say yes, and it wouldn't mean anything, and then I'd have spent it." She got up onto one elbow. It took a while. He did not help; also treaty. "So. When you get there, there are six people in a pumphouse. There might be four. There might be none. Whatever the number is when you arrive, I want it. Whatever it is when you leave, I want that too."

"Eliana—"

"And I want names. Not a count. Names. The ones that live, the ones that don't, the ones you find already dead. And the ones on the other side, Leon. The ones in the ships. If you can get them."

"And if I can't."

"Then you say out loud, to me, that you couldn't. Instead of not mentioning it."

He did not answer.

"You'll want to round," she said. "You'll want to come in here and say most of them made it, because that's a kind sentence and you're kind at me. Don't. If it's zero, say zero. Don't give it a shape."

"That's a lot of names."

"You have an eidetic memory and no other hobbies."

"And if the far side is four hundred?"

"Then it'll take you a long time," she said, "and I'll be here, and I'm not going anywhere fast." She held his eyes. "That's the ask. Come back or don't. But don't come back and hand me a summary. I'm not the public. I'm not a village square. I've had my face on the side of a grain silo and I've had strangers price me over a table in front of me, and I have exactly one person left whose job is to give me the actual numbers."

The concentrator hummed. Pip's light stayed low.

There is a name I have had in my mouth for sixteen months, he thought. He had three children. I have never once said it in this room.

"I'll bring you the names," Leon said.

She searched his face the way she had on the stairs at Ninepenny, and whatever she found there she let him keep, and he understood — again, exactly as before — that letting him keep it had been a decision she made.

"Good," she said. "And the coat."

"And the coat."

Unit-02 stood on the pad at 05:11 with the wings furled and the funnels racked and its head up for the first time. The laminate had cured overnight to gloss, and the rust-and-bone light came off its shoulders in one unbroken line from collar to hip.

The picket was gone. Two hundred and thirty-one hours of window left. Running east to west past the observatory shell and out over the horizon was a trench eleven kilometres long and four metres wide, straight to within the width of a hand, and it would be there in ten thousand years, because nothing on this world had ever eroded anything.

He looked up before he climbed in, because it was worth doing properly.

The sky at 0.4 bar is not blue and it is not black. It is a thin exhausted violet that lets the bright stars through in daylight, and Meridian-7 has no moon and no weather and nothing else to offer, so what you get is the fixed stars, holding still, doing what they had done for eleven hundred years while the Reach forgot how to be afraid of anything. He found the ecliptic. He found the ones he knew by name.

Low in the east, a point of light was moving. The picket, outbound, twenty hours gone and running its arc. He stood in the cold with his hands at his sides and watched it. Fifteen seconds of arc in four minutes, near enough. He did the mathematics and got the right answer, which he had also got eleven days before the invasion, and this time he did not go inside. He watched until it cleared the ridge.

Four hundred and eleven perforations down and two decks along, a file designated Omega-7 sat sealed behind a key that only he had. He thought about it once, the way you touch a tooth with your tongue to check that it still hurts. Then he stopped, and climbed the ladder, and pulled the cradle shut.

Coupling at 05:19. 89.4.

The drives came up. The pad went white.

He put the nose east, toward eleven light years of occupied dark and a pumphouse at Kessler Flats where the number was six and had not been updated in nineteen hours, and he went.