The Red Seeds

I.

The reactors fell like seeds, and seed was the honest word, because nobody doing the flinging could say where any one of them would grow.

Earth had done the flinging. A scatter of solid little suns, each sealed in a pod with a parachute and a nose cone packed with sand, thrown down out of Mars orbit a hundred at a time and left to land however the planet decided. Some came down soft, into the deep ice of the northern plains, and those were the lucky draws: a reactor cradled in a billion tons of frozen water, which was air and drink and coolant and everything a colony needed to climb up out of nothing. Some came down hard, onto bare rock or into the throat of some canyon, and those cracked open and died. Or, worse, half-died, and waited.

You found a reactor, you woke it, you built your life in a ring around it. That was the whole story of how people came to live on Mars. There was no grand arrival, no carried-down city, no fleet. There was only the long patient walking out across the rust until your rover's counter ticked up against a buried warmth, and the digging, and the finding, and then pressing twelve volts into the thing the way you'd breathe on a coal to bring it back.

Saleh was a soft draw. Karl had not been alive for the finding of it, but he had heard the story a thousand times: how the first keepers had cut down through forty meters of dirty ice to reach the pod, how the core had been sitting cold and patient in its sand for who knew how long, how an old woman had clipped a rover battery to the contacts and warmed the moderator block until the neutrons began to multiply and the heat came up on its own, gentle and then sure. After that, the ice gave them water, and the water gave them air, and the warmth gave them everything else. By the time Karl was keeping the reactor himself, Saleh was nine hundred people under a roof of spun glass and packed regolith, with greenhouses that smelled of tomatoes and wet earth, and a square where the children played a game with a ball that never came down quite the way it would have on Earth.

It was a comfortable place. It was also a poor one, and a small one, and Karl would not understand until much later how easily those two things had lived side by side. The reactor gave them power and the ice gave them water, but power and water were very nearly the whole of what Saleh had, and there was never quite enough of anything else. When the fever came through — the one that took Karl's parents and Kel's in a single season, that carried off a tenth of the colony before it burned itself out — there was nothing to be done but nurse the sick and dig graves for the lost, because medicine for a thing like that came from Earth, and Earth was far away and did not come often. And they could not go to it. A colony was married to its reactor the way a tree is married to its roots: the deep ice, the metals, the rich ground, any of it might lie a thousand kilometers off across country no rover could cross before its batteries failed, and so you stayed where your one good draw had landed and made do with what was in reach. They were poor the way people are poor who have just exactly enough to live and not one thing more, and they had made their peace with it, and called the peace contentment, and never once thought to call it a cage.

That was the thing Karl would remember most, afterward, with something close to shame: how comfortable it had been, and how little they had known.

II.

Karl was the keeper, which meant the reactor was his to love and to mind.

He had learned it from Tobin, who had learned it from the old woman, and the lesson that mattered most was the one Tobin gave him on his first day in the vault, both of them standing in front of the sphere with their hands behind their backs like people at a graveside.

"It can't hurt you," he'd said. "Remember that before you remember anything else. They built it so it can't."

He'd explained it the way he explained everything, slowly, with his hands. The core was a ball, perfectly round, so it would run no matter how it came to rest, no matter which way a pod tumbled down through the sky. It had no pumps that could seize, no rods that could jam, no fluid that could boil away. It turned its heat straight into current through banks of solid material with no moving part anywhere in them, and what could not move could not break. And at the heart of it sat the mercy, the part Tobin made him say back until he had it cold: the fuel was a hydride, and a hydride was a coward. Heat it past where it liked to be and it simply stopped doing its job. Stopped slowing the neutrons. Stopped feeding the fire. A reactor like this one could not run away and melt, the way the old Earth machines were always threatening to, because the hotter it got, the harder it tried to switch itself off. Push it, and it pushed back toward cold. It wanted, more than anything, to be safe.

"You could throw it off a cliff," Tobin said. "You could shoot it. People did, once, before they trusted it, just to see. It shrugs. It was made by people who were tired of being afraid."

Karl had loved it for that. For years he went down into the vault and listened to its small ticking warmth and felt the way you feel near a large sleeping animal that has decided not to harm you. It was the safest thing he knew.

He wishes now that nobody had ever told him it could be made unsafe. He wishes he had never been clever enough to work out how.

There was a story they told at Saleh, the way every colony told some version of it, about a man who had gone out and never come back. Not a hero and not a villain in the telling, just a man who had never quite fit the shape of a person; who looked too long at things, and thought sideways, and kept to himself so hard that he had made himself into a colony of one. They had not hated him. They had simply let him drift, the way water lets a thing drift that it has decided not to hold, until one day he loaded a rover with everything it would carry and rolled out into the rust alone, and the rust took him. People said he'd gone looking for a reactor of his own. People said a lot of things. It was the kind of story you told to children to keep them close to the lights.

III.

The first sign of the Nuclear God came when Cassan stopped answering.

Cassan was a nexus four days east, a hard little place built around a reactor that had dented on landing and been nursed back to half its rated power. They traded by radio and, twice a year, by rover. Then one season the radio from Cassan went to noise, and the rover that went to check did not come back, and the rover that went to find the first rover came back early, with three people in it who would not speak for a day and a night.

When they did speak, it was about a sound. A sound you felt in your chest before you heard it, they said, and a shape on the horizon too large to be a machine and too deliberate to be a storm, and a light around it that made their counters scream and their skin tighten as if the air itself had teeth. They saw the first rover and ran as fast as they could before the sound could catch them.

Cassan was not damaged, they said. Cassan was gone. The domes were peeled off their anchors and lying in the sand, some kilometers away. The reactor that had been its heart was simply not there anymore, and the people were in the open, and the open had not been kind.

The word that came with the refugees was a strange one, and it spread through Saleh faster than sense could chase it. They had seen a god, they said. Not a machine. A god. They knew it was foolish even as they said it, but they had no smaller word that fit, and so the foolish word was the one that stuck, and within a week there was not a soul in Saleh who did not lie awake some part of the night listening for a sound that hadn't come yet.

IV.

It came on an ordinary afternoon, which was the cruelty of it.

Karl was in the greenhouse with Kel, his brother, who was sixteen and all elbows and who he had raised since the fever year took their parents, when the floor began to hum. Not the floor. The bones of him. The water in the tanks went into rings. And then he was at the window and there was a thing walking toward Saleh out of the east, and Tobin was right, and Tobin was wrong, because what was coming was a reactor, he could see that much, he would know that shape anywhere — but it had been built into the chest of a thing the size of a tower, a walking red mountain of welded wreckage with a furnace where a heart would be, and the light coming off it was the light of a core that had been made to do the one thing he had been promised it could never do.

Its maker had defeated the mercy. That was the obscenity he understood in the first instant, standing at the glass with his brother's hand finding his sleeve. The man had found a way to keep the coward fuel from running. Cooled the moderator hard, maybe, kept it cold and faithful even as the fire climbed, so that the thing could not switch itself off, so that it ran and ran past every limit its makers had begged it to keep, and bled out its fury as heat and as the invisible killing light that made the air around it shimmer like a thing in pain. The safest object he had ever loved had been turned, by patience and by genius and by some terrible need, into the least safe object on the planet.

What happened to Saleh after that took less time than it takes to tell. The domes came off. The greenhouses went to splinters and frost. The walking thing moved through the place he had lived his whole life and took what it wanted of their stores and their metal and broke the rest, not in anger, he thought, because there was no anger in it, only a kind of vast indifference, the way you might step through a spider's web without ever knowing it was a home. Tobin died in the vault, trying to do something for the reactor that had no doing left in it. He found that out later. In the moment he found only Kel, and a low place in the rubble, and his own body bent over the boy, and the long impossible minutes of waiting for the shadow to pass.

Because there was one mercy left, and it was a black one. The killing light came off the thing in every direction, the way light comes off a lamp, but in front of it, in its own long shadow, you were spared. The reactor shield that protected the pilot of the machine from the radiation created the only safe zone within a hundred meters. And you had to either file in, square in front of the Nuclear God, or have your cells ripped to shreds inside your body by subatomic particles. So he had learned the first lesson of the new world while he lay in the wreck of the old one, learned it in his skin without anyone to teach him: There is no mercy.

For now, it was all he could do to hide. Emergency closets and safety rooms were standard procedure for colonies on Mars, and as long as he could stay still and silent, he would have a chance to outlast the assault.

It rolled off to the west toward the next bright place, and left them in the cold and the dust, and Mars learned the shape of a god in its sky.

V.

Nine hundred people had lived at Saleh. When Karl stopped counting, because counting was a thing he could not keep doing and stay upright, there were a little under six hundred.

They buried what they could and burned what they couldn't and listened to the wind, and the question sat in the middle of all of them like a stone nobody wanted to be the one to pick up. They could lie down. That was a real choice and Karl never pretended otherwise; there is a kind of grief that makes lying down look like the only honest thing. Or they could do the other thing. The unthinkable thing. The thing the man had done.

They had reactors. Cracked ones, half ones, the dead-and-waiting ones scattered all over the plains that nobody had ever bothered to wake. And Karl was a keeper, and Karl, God help him, had stood in a vault for fifteen years learning exactly how these machines were meant to be kept safe — which meant he was one of the only people alive who could begin to work out how to make them otherwise. How to cool a moderator past its faith. How to pin a coward open. How to take the mercy out, and match the new world.

He did not decide it in a noble flash. It came on him slow, over the burials, a cold and rising pressure behind the eyes that he would only later have a name for. It felt less like a choice than like a door closing behind him, every other door, until there was just the one in front of him with a single hard word written on it, and the word was the only way through. He understood, standing in the ruin of the safest place he had ever known, that necessity is not a kind teacher. It does not hand you the answer. It locks you in a room with the problem and tells you that you will solve it or you will die, and then it makes you pay for every step of the solving in the only currency it takes.

He put his hand on the door. They all did. That was the moment Saleh stopped being a colony and started being something else.

VI.

The first year of the work killed nearly as many of them as the Nuclear God had.

This is the part the songs never get right, or get right only in passing, because it does not flatter anyone: that learning to make a weapon out of a machine built specifically to never be one is a thing you learn by failing, and every failure has a body under it. They cracked open cores they did not understand. They cooled moderators and watched, breathless, as the power climbed past the line and kept climbing, and twice it climbed faster than they could choke it back, and a core that should have been incapable of running away ran away into a light that took a whole salvage crew and the rover they'd come in, all at once, gone between one breath and the next. They built crude controls out of whatever they had. Karl would dream for the rest of his life about a control they had propped open with a screwdriver because they had nothing better, and what the screwdriver did when it slipped, and the thousand small failures dressed up as one large one.

They buried nearly as many as the Nuclear God had, and they did it with their own hands, building the very thing that was killing them, and they did not stop, because there was no choosing left, and a thing you cannot choose against you simply do. Karl stopped being the man who had loved a sleeping animal in a vault. He got quieter. His hands got steadier and his eyes got further away. Kel watched it happen to him, and he watched it begin to happen to Kel, and neither of them said the thing they were both thinking, which was that the man who had done this to them had probably started out no stranger than they were now.

That was the worst of it, on the worst nights. The growing certainty that the Nuclear God had not been born a god. That he had been a person, once, alone in front of a broken machine with no way home, and that the same hand that was carving them now had carved him then, and that the only difference between him and them was that they were right.

VII.

He came back.

Of course he came back. The universe that had thrown the seeds down at random and let half of them die for sport was not going to let four hundred grieving people climb halfway up out of the dark and then leave them be. He came over the dunes a second time, when they had just begun to have something worth losing again, and he put it all to the test, and he smashed it, and he poisoned the ground where it had stood, and there were graves to dig again, though fewer this time — far fewer than the first.

But something had changed, and it had changed in them, and it was not a thing Karl could feel proud of even though it was the only reason any of them lived. The first time the Nuclear God came, Saleh had run. This time, when the air went to teeth and the shape came up out of the east, the people of Saleh did not run. They had been carved once already. There was a hardness in them now where the softness had been cut away, and the hardness did not break. They got their wounded hidden quickly. They saved the work they could. They watched him go, and they did not weep the way they had wept the first time, and Karl understood that this, too, was something they had lost — that the capacity to be destroyed by a thing is its own kind of innocence, and theirs was gone. There were three hundred of them now. Fewer had died this time than the time before, and fewer that time than the first — and the steady shrinking of the cost was the truest measure of what they had let themselves become.

They picked up their tools. They sharpened their knives. And they went back to the work with a cold and total focus that would have frightened the people they used to be.

VIII.

If you cannot kill a god, you build one. And if one is not enough — and one would never be enough — you build a dozen more behind it.

That was the shape the answer finally took, after the failures and the burials and the long brutal schooling in how these machines died. They learned to make the cores run hot and stay running. They learned to wrap them in shadow shields so a pilot could ride in the one safe cone behind the killing light instead of dying in it. They learned to give the heat legs. The whole of what was left of Saleh bent itself to the single task the way a colony had once bent itself to greenhouses and water, except that the thing they were growing now was a company of walking suns, and the field they grew it in was watered with everything they had.

There was a hard limit on them, and it shaped everything that came after. The machines could not stand together. Each one threw the same killing light the god threw, with the same small cone being the only safe zone, and two of them within a few hundred meters of each other would cook the other's pilot in his shielded seat, blind the other's instruments, poison the ground they shared. They could not mass, at least for long. They could not huddle behind a wall and wait. Every giant they built was an island that had to hold its distance from every other, and so when they finally set them out around what was left of Saleh, they set them wide across the broken plain, each one walking its own long patrol, each one alone in its sector with kilometers of empty rust between it and the next. It was an army that could never form a line — a scattering of separate gods that could come together at one place and one moment only, when every last one of them was converging on the same enemy at once, and not one second before.

Karl had led it. He had not asked to and did not want to and was the only one who could, and so he did, and it hollowed him out and filled him back up with something harder. He built the first machine himself, the champion, the best of everything they knew, tall enough to look a god in the eye, and he rebuilt it a hundred times in his mind before it ever stood. And then he built the dozen that would stand behind it, sprawled out across the plain, these terrible children of their own necessity, every one grown out of grief and need, every one a thing he would once have called an abomination, and he felt for them, God forgive him, something close to love.

Kel drove the champion. The soft boy Karl had raised, all elbows, who had been afraid of the dark when he was small — that boy climbed up into the chest of the best thing Karl had ever built and learned to make it walk. Karl let him. Letting him was the price, and Karl had stopped, somewhere back along the road, being able to refuse a price. He told himself the champion was the strongest of them, which was true. He did not let himself finish the other thought — that even the strongest of them would not be enough.

IX.

He came over a hill into the champion's sector, expecting an easy thing to break, and found Kel's machine standing in his road.

Karl watched it from the ridge through a haze of dust. He watched the god slow, watched him take in the shape that stood waiting for him, tall as he was, turning to meet him. The god had walked over a whole world and never once met a thing that could meet him back. He squared himself. And somewhere out across the plain, in a dozen other sectors, a dozen other machines turned at once toward the place where the light had spiked, and began to run.

They were minutes away. That was the whole of it — the entire terrible arithmetic of that afternoon. The others were minutes out, scattered wide because they had to be, and the champion was here now, and the only question left in the world was how long one machine could hold a god.

It could not win. Karl had known that building it, and Kel had known it climbing in, though neither of them had ever said the words. A god is a god, and theirs was only the first of its kind, and the Nuclear God hit it like a force of nature. But the champion did not run, and it did not fall easy. It held. It got its hands into the thing and made it work for every meter, and every second it bought with its body was a second a dozen other machines were spending to cross the rust — and Karl stood on the ridge and counted those seconds and understood exactly what the counting cost.

The champion went down hard. The Nuclear God tore it open and drove it into the ground and stood on the wreck of the best thing Karl had ever made, the machine with Kel inside it, and made a sound that shook the ridge. And the hope went out of three hundred people all at once, like a snuffed light, because the champion was broken in the dirt and the Nuclear God still stood — and for the length of one held breath it looked as if the holding had been for nothing, and the world was lost.

Then the dozen arrived.

They came in off the plain from every direction at once, because the champion had bought them the time to converge, a dozen walking suns built from a dozen kinds of loss, and they fell on the god from every side in the same moment, and there is no holding against that, not even for a god. They paid the planet back for every year of it. They did not stop when he went down, and they did not stop when the sound went out of him, and they did not stop until there was nothing left of the terror of Mars but a stain on the ground and a silence so wide you could hear the wind walk across it.

A dozen red giants stood in the dust where the Nuclear God had fallen. And the champion that had bought them the ground to do it lay broken open among them, cooling, empty inside.

X.

The peaceful little place that had prayed to be saved was not saved. It had been gone since the first afternoon, and no one was ever going to give it back. And now Kel was gone with it — the last warm thing, the boy he had raised up out of the fever year, the whole reason he had picked up the work in the first place — paid out into the red like everything else, and the red gave nothing back either.

They had won. Karl made himself say it, because it was true and the dead had earned the saying of it. They had taken a thing that walked over their world like a god and ground it into the dust, and the people of Saleh would live, and their children would live, behind a hardness that nothing was ever going to break again. But he stood among the machines that had done it, in the place where his brother's machine lay broken into scrap metal, and he understood at last what they had become, and it was not the understanding of a victory.

They had not beaten the Nuclear God. They had become him — a dozen times over and on purpose — and they had fed the becoming with everything they had, down to the last soft thing any of them owned. Karl had owned exactly one soft thing at the end. He had put it up into the chest of the strongest machine on the field and sent it out to hold the line, and it had held, and that was the price, and he had paid it the way he had learned to pay everything: in full, and without ever being offered the choice to refuse.

He had believed, once, in the vault, with Tobin's voice in his ear, that there was a difference between the two ways a seed could grow: between the colonies watered with meltwater and ice into something soft and happy, and the ones watered in blood into something that could not be killed. He had believed there was a line between them. Standing there a conqueror in the ruins of everything he had been, with his brother in the ground and the wind moving over the dozen and the dead, he could not find the line anymore. He had paid so much, and the paying had worn the difference clean away, until blood and water ran together in him and came out the same. That was the last thing the Nuclear God took from him — or gave him, depending on how you keep such accounts. Not his brother. His brother was only the cost.

There would be more reactors. There were always more, scattered dead across the plains, waiting in their sand for somebody with a battery and a need, and the people of Saleh knew now exactly how to wake them, and exactly how to cut the mercy out of them, and exactly what such a thing cost, and exactly that they would pay it. Their world would never look like the gentle places — the lucky draws, the soft-landed Edens still going about their comfortable lives somewhere over the curve of the planet, whole and ignorant and afraid of nothing. Karl's world had walking suns in it, and a stain where a god had died, and a grave with no body in it, and a hardness in the eye that the gentle places would not have recognized as a human thing. And he no longer recognized them as one either.

And the thing Karl could never have said aloud, and least of all to a grave with no body in it: the new world was better. Not kinder — it would never be kinder — but better, in every way a life can be measured that is not measured in the dead. The giants that had killed a god could walk, and a thing that could walk could go anywhere. They would cross the dead country now, the thousand kilometers of rust that had penned every soft colony inside the reach of its one reactor; they would put their hands on the deep ice and the metal and the rich ground that Saleh had been too poor and too rooted to ever touch. They would mine. They would move. They would build, and spread, and put down the next mad thing that came crawling up out of a cracked seed before it ever swelled into a god, and hold an order over the red that the gentle places, for all their contentment, had never once been strong enough to keep. And when the hard people looked back at the old comfortable life — the one Karl still woke in the night grieving for — they would not see a paradise that had been stolen from them. They would see a cage they had been too frightened to leave, and a fever they had been too weak to fight, and a smallness they had mistaken all their lives for peace. They would not want it back.

It was the knowledge that the cost had not been too high. That nothing would be, ever again. And that was why the people of Mars, having watered their hard red world in blood to make it theirs, were never going to stop.