The filter woke wrong.
It started at five, the way it always did. The hum came up through the boards and began to climb. Then, halfway up the walls, it caught on something. A grinding. A stutter. A sound like a cart wheel with a stone in it.
I was out of bed before it finished.
The filter lived in a shed built into the back of the house, a squat thing of steel and ceramic about the size of an oven, with pipes running off it into the walls like roots. Father had built most of it. The housing, the ducts, the ceramic plates that caught the poison out of the air: all of that was his, made out of the valley's own rock. I'd rebuilt half of it since.
But not the heart of it.
The heart was a sealed gray box bolted to the base, with a fan on one side and a thick braid of wires on the other. A motor controller. Military, Father said, from before the war. It told the fan how fast to spin and when, and the ceramic plates how hot to run, and it did a hundred other small things too fast for anyone to see.
It was making the noise.
I put my hand on it. It was hot. Much hotter than it should have been.
I looked at it. Really looked, the way Father taught me, down past the paint and the steel case into what it was made of. Copper. Silicon. Tiny threads of gold. Plastics I could name and a few I couldn't. Thousands of little parts on a green board, arranged in patterns too small and too many for me to follow.
I could have turned every atom in that box into something else.
I couldn't have made another one. I didn't understand what it was for, molecule by molecule, any more than I understood bread.
Genny appeared in the doorway behind me in her nightshirt, listening.
"Controller," she said.
"Controller."
"How long?"
I listened to it grind. "A week. Maybe less."
She didn't say what we were both thinking. Without the filter, the air in the house would go bad in three days. Mother's lungs would go first.
"There's a spare," Genny said.
"There's a spare at the highway."
"Then we'll go to the highway."
I didn't want to leave Mother alone.
I said so at breakfast, which I brought down to the front room. She was sitting up a little, which was good, and had eaten one bite, which was not.
"I'll go by myself," I said. "The girls can stay with you."
"You can't lift the crates," said Mother.
"I'll find a way."
"You'll float them one at a time and take three days and come home with a nosebleed." She looked over my shoulder at Genny, who was leaning against the doorframe pretending not to listen. "Genny goes with you."
"And I'm going," said Garnet immediately.
"You're staying with Mother."
"I'm going."
"Garnet—"
"Lucas," said Mother.
I stopped.
"I'll be perfectly fine for a morning," she said. "I have water. I have the stove. I have a gold fishing weight for fish that don't exist." She held it up. It caught the window light. "And I would like, very much, for my three children to go somewhere together and come home together and tell me about it. Can you do that for me?"
It wasn't really a question. It never was, with her.
"Back by noon," I said.
"Back by noon," she agreed, and closed her eyes, and smiled.
The highway was six miles east, over the ridge.
We wore Father's masks: soft gray things that sealed over the nose and mouth, with a little ceramic plate on each side that did the same job as the filter, only smaller. Garnet had painted a smile on hers years ago. It had faded until it looked smug.
At the top of the ridge, the green ended.
It always surprised me, even though I'd crossed it a hundred times. One step there was grass under my boots, Father's grass, short and tough and alive. The next there was ash. Gray, fine, drifted into long low dunes by thirty years of wind. Here and there something stuck up out of it: a fence post, the roof of a car, a black stump that had been a tree. In the distance, the bones of a town, its buildings standing with their windows all blown out, like faces with no eyes.
Nothing moved out there except the dust.
Garnet stopped singing.
She always did, at the ridge. Nobody had ever told her to. She just stopped, and took my hand, and held it until we were back on the other side.
We walked.
The convoy was where Father left it.
It lay along the old highway for half a mile, half-buried in ash: forty or fifty vehicles nose to tail, as if they'd all stopped at once and nobody had ever started them again. Buses, mostly. Big ones, the long kind with windows down both sides. Military trucks between them, square and green under the dust. A tank on its side in the ditch, its gun pointing at nothing.
Father told me about it once. In the last month of the war, the government had tried to move everyone they could into the domes. Every bus and truck left in the territory, running toward the bubbles in long lines like this one. Most of them made it.
Not this one. The invaders had come down on it from the sky.
Nobody had been inside these buses for thirty years. There was nothing left in them to be afraid of. That didn't stop it being a bad place to stand. The air felt heavy. The quiet was the wrong kind of quiet.
On the side of the first bus, under the dust, you could still read the painting: DOME TRANSIT. REGISTERED CITIZENS ONLY. Underneath, smaller, in red: Modified personnel report to military transport.
Genny read it out loud.
"What's modified personnel?" Garnet asked.
"Us," said Genny.
"Mother and Father," I said. "People like them."
"Why couldn't they go on the bus?"
I didn't know what to tell her. I didn't know, then, how much there was to tell.
"They had their own trucks," I said, which was true, and kept walking.
The supply truck was two-thirds of the way down the line.
I knew it because Father had marked it, a long time ago, with a scratch on the door in the shape of an X. He'd taken the first controller from it years before I was old enough to come. There was another one still inside, in a crate in the back, he'd said. A spare. For when we needed it.
The problem was the bus.
At some point in the last thirty years, a storm or the ground shifting had tipped the bus beside it over. It lay on its side across the back of the supply truck like a fallen tree, crushing the canvas roof flat. Through a gap at the bottom I could see the corner of a green crate, stenciled with white letters. And on top of it, eleven tons of steel.
I looked at the bus.
I could have turned it to sand. To air. To water. I could have made it disappear between one breath and the next. But the crate was underneath, and if I changed the bus the wrong way, everything under it went with it. The controller inside was a book I couldn't read. If I so much as scratched it, we'd have walked six miles for nothing.
"Genny," I said.
She was already rolling up her sleeves.
"Gently," I said.
"I know gently."
She walked up to the bus. Put out one hand, palm flat, not quite touching the dusty roof. Breathed out.
The bus lifted.
It came up off the supply truck all at once, slowly, the way you'd lift a blanket off a sleeping cat. Eleven tons. Dust poured off it in sheets. The canvas underneath sighed and sprang partway back up. A shower of old glass fell out of its broken windows and glittered in the air, and Genny held the whole thing there, ten feet up, perfectly level, with one hand.
She was nine. She was the size of a broom.
She turned slightly, and the bus turned with her, and drifted twenty yards to the side, and settled down on the highway on its wheels for the first time in thirty years with a groan of old springs.
Genny lowered her hand.
"There," she said. "Gently."
Garnet clapped.
I crawled into the back of the supply truck and found the crate. It was intact. Inside, packed in gray foam, exactly where Father said it would be, was a sealed gray box with a fan port on one side and a braid of wires on the other.
I held it up. Genny let out a breath I don't think she knew she'd been holding.
That was when Garnet said, very quietly, "Lucas. There's people."
There were four of them.
They were on the embankment above the highway, maybe a hundred yards back, beside a rusted pickup truck with its bed full of scrap. Two men, a woman, and a boy not much older than me. All of them in patched coats and homemade masks, the kind made out of cloth and charcoal and hope. One of the men had a rifle slung over his shoulder. The woman had a crowbar.
Scavs. They worked the dead towns and the old highways for anything worth trading at the ridge settlements: copper, glass, tools, tinned food from before the war. Father said there were a few hundred of them left in the territory, maybe. Unmodified people who'd never got a place in the domes, and had been surviving out here ever since on whatever the war left lying around.
They had stopped dead. All four of them were staring.
Not at me. At Genny. And at the bus, sitting on its wheels in the middle of the highway, still shedding dust.
Nobody moved.
The wind blew ash across the road between us.
I put the controller down very carefully on the floor of the truck bed. Then I stepped out into the open, in front of the girls, with my hands where the scavs could see them.
"We're just here for parts," I called. "We're leaving."
The man with the rifle didn't take it off his shoulder. He didn't need to. His hand had gone to the strap.
I looked at the rifle.
It was steel, and wood, and a little brass in the cartridges. I could have turned it to sand in his hands. I could have turned all of it to sand: the rifle, the crowbar, the truck. I could have turned the ground under them into anything I wanted. I could feel the shape of every one of those things, the way you feel the edges of a room in the dark.
I didn't do any of it.
I kept my hands out, and I waited.
The boy was the one who spoke. His voice came out high and cracked through his mask.
"Scarecrows," he said.
The woman grabbed his arm. The man with the rifle took a step backward. Then another.
And then they were running. All four of them, scrambling back up the embankment and throwing themselves into the pickup, which coughed and caught and fishtailed away in a spray of ash. The scrap in its bed rattled and bounced. A coil of copper wire fell off the back and lay in the road.
They didn't look back.
We stood there until we couldn't hear the engine anymore.
"What's a scarecrow?" Garnet asked.
She knew what a scarecrow was. She hugged one every morning. She was asking what they meant.
Genny's face was very white behind her mask. Her hand was still half-raised, the one she'd lifted the bus with. She lowered it slowly and pushed it into her jacket pocket.
"It's what they call us," she said. "Out here. People like us."
"Why?"
Genny didn't answer. She looked at me.
I'd heard the word before. Not often. Once from a trader at the ridge settlement, when I was twelve, before he saw my face and decided to be polite. Once in one of Father's notebooks, written in the margin in his small square hand and then crossed out so hard the pen had torn the paper.
I knew what it meant. The domes had built people like our parents to stand between them and the invaders. They'd made them terrible on purpose, so that anything that came at the domes would be afraid. And when the war was over, they'd left them standing out here in the dead fields, still terrible, with nothing left to frighten off.
Scarecrows.
"Because they're scared of us," I said.
"But we didn't do anything."
"I know."
"Genny just moved a bus."
"I know, Garnet."
"She moved it gently." Garnet's voice was rising. Her eyes were wet above the smug painted smile. "She didn't hurt anybody. She put it down nicely."
"I know."
Genny took her hand out of her pocket and put it on her sister's shoulder. Just rested it there. It was the most Genny thing she could possibly have done.
I looked up the road where the truck had gone.
And I understood, finally, why Father had built our house at the bottom of a valley that nobody had any reason to look at, six miles from the nearest road, with a ridge between it and everything else.
It wasn't the invaders he'd been hiding us from.
We didn't go home the straight way.
We went north first, two miles out of our way, along a dry creek bed where the ash was thin. Every few hundred yards I stopped and turned back and looked at the ground behind us, and made our footprints into smooth gray ash again, as though no one had walked there at all. Father taught me that. I'd thought, when I was small, that it was a game.
Genny carried the controller the whole way, floating it in front of her at chest height, never letting it bump into anything. She didn't say a word.
Garnet didn't sing until we were over the ridge and back on grass. Then she started, very softly. The same wandering tune with no words.
We were back by noon.
Mother was awake. She'd been watching the ridge through the window, and she knew before we'd come through the door. I don't know how. She always did.
"Tell me," she said.
I did. All of it. The convoy, the bus, the scavs, the word. Garnet sat on the bed and told her own version at the same time, louder, which made it longer. Genny stood in the doorway and said nothing at all.
Mother listened. When I got to the scavs, her hand stopped moving on Garnet's hair.
"Did they follow you?" she asked.
"No."
"Did they see which way you went?"
"We went north first. I covered the tracks."
She let out a long breath. Her hand started moving again.
"Good," she said. "Good. That's what your father would have done."
She said it as though it was a comfort. I could see her deciding not to say anything else.
I fitted the new controller that afternoon.
It took three hours, because I went slowly. Father's diagrams were taped to the inside of the shed door, yellowed and curling, and I followed every one of them twice. When I was done, I closed the housing and stood back and waited.
The filter caught. Hummed. Climbed.
No grinding. No stutter. Just the low, steady purr in the walls, the sound I'd fallen asleep to every night of my life.
I went out into the wheat after dark.
The scarecrow stood where it always stood, in Father's patched coat, with its faded face turned up to the moon. The ice up there was bright tonight.
I looked at the scarecrow for a long time.
I thought about the boy on the embankment, his voice cracking through the mask. I thought about the bus settling down on its wheels. I thought about Father writing that word in his notebook and then tearing through it with his pen.
I thought about why a man would build a scarecrow in a field with no crows in it, and dress it in his own coat.
The wind had pulled the collar crooked.
I fixed it. Then I put my hand on its shoulder, the way Genny had put her hand on Garnet's, and left it there for a while, and didn't say anything at all.