SEVENTH

Chapter One: Cold Floor

The floor was cold enough to hurt.

That was the first fact of his existence: cold, ridged metal pressing a grid pattern into his cheek. The second fact was sound — a low hum coming up through the plates, steady as a sleeping animal's breath. The third fact was that he did not know his own name.

He lay still for a long moment, waiting for the knowledge to arrive the way a word arrives when you stop reaching for it. Nothing came. There was no childhood behind him, no house, no face of a mother or a friend. There was only the hum, the cold, and a dull ache at the base of his skull, as if someone had set something down there too heavily and walked away.

He pushed himself up onto his elbows.

The corridor stretched in both directions, wide enough for three people to walk abreast, lit from recessed strips where the wall met the ceiling. The light was the color of weak daylight and gave off no warmth. The walls were pale gray composite, seamed every two meters with thin black lines. Some of the seams were perfectly straight. Others curved in ways that made his eyes want to follow them.

He stood. His legs worked. He was wearing dark trousers, boots that fit him well, and a heavy canvas jacket with a torn cuff. He patted himself down the way he imagined a man might who had lost something. His pockets held nothing at all.

But there was a stiffness in the jacket's lining, low on the left side, that did not feel like fabric.

He worked his fingers into a small gap in the seam and pulled. Thread gave. Inside, folded into a square no bigger than a stamp, was a piece of paper.

He unfolded it with hands that shook more than he liked.

SEVENTH

418302

That was all. Block capitals in dark pencil, pressed hard enough to dent the paper. Below the word, the six digits, spaced evenly, no punctuation.

He read it eleven times. He held it up to the light and turned it over, and the back was blank. He said the word aloud, and his voice came out cracked and unfamiliar, and the corridor swallowed it without echo.

"Seventh," he said again. "Four one eight three zero two."

It meant nothing. It meant everything, because it was the only thing he had.

He folded the paper carefully along its old creases and pushed it deep into his inside pocket, and then he began to walk, because standing still felt like agreeing to die.

The corridor ran straight for perhaps eighty meters and then split. He took the left branch, and it opened into a chamber with a ceiling so high the light strips receded into a gray haze. Walkways crossed the space above him at four different levels, some of them transparent, so that he could see the pale undersides of their supports and, further up, more walkways still, and above those a suggestion of more. There was no sky. There was no roof he could see, only distance and dimness.

There were no windows anywhere. He understood, in a way he could not have explained, that this was important. A building has an outside. This place had the confidence of something that did not.

He found a wall panel that dispensed water when he put his palm against a matte square beside it — a thin stream into a shallow basin, tasting of metal and faintly of nothing. He drank until his stomach hurt. Beside it, a second panel produced a gray-brown paste in a paper cup. It tasted of yeast and salt. He ate it and felt his hands steady.

Someone had made this place. Someone had installed water and food and light and had built no windows.

He kept walking.

He was three hours into it — he counted by breaths and by the ache in his feet — when he found the marks. On a wall at a junction, someone had drawn an arrow in something that glowed faintly green, and beside it three short slashes. Further on, another arrow, and a symbol like a crossed-out circle over a doorway.

He put his fingers to the chalk. It came off on his skin and glowed there. He rubbed it away against his trousers, and for the first time since waking he felt something other than fear. Someone else was alive in here. Someone had a system.

He followed the arrows until they stopped at a T-junction where the chalk had been scuffed almost to nothing, and there he stood, turning slowly, trying to decide, and that was when the sound came.

It was not loud. It was a sensation more than a noise, a fast dry crackle that passed through his teeth and the bones behind his ears. Every hair on his arms stood up. The light strips flickered once, a stutter so brief he might have imagined it.

Then the hum in the floor changed pitch. It climbed.

Niko — he did not know yet that this was his name, but the mind insists on calling itself something, and later, when he learned it, the memory of this moment would rename itself — Niko turned in a full circle, and the walls began to move.

Not fast. That was the horror of it. The walls moved with enormous, patient authority, like ships docking. The corridor on his left slid sideways, its opening narrowing centimeter by centimeter. The ceiling above the T-junction dropped a hand's width and locked with a clunk that he felt in his knees. Somewhere out of sight, something the size of a warehouse rotated, and the vibration of it came through the plates as a long grinding purr.

He ran.

He ran because the narrowing corridor was the only one still open, and he made it through with the walls close enough to scrape his shoulders on both sides, and then he was in a longer passage where the floor was tilting.

It tilted slowly, a few degrees, then more. He scrambled up the incline. The plating under his boots was smooth and gave no grip. Ahead, a doorway stood at the high end of the slope, and beyond it, blessedly, level floor.

Behind him the corridor's low end split open.

He felt it before he heard it, a change in the pressure of the air, and then the sound arrived and it was the worst sound he had ever heard, which was not saying much, since his memory was one hour and forty minutes deep. It was the sound of teeth. Of enormous, unhurried machinery meshing. He looked back once, and through the widening gap in the floor he saw them: gears, dozens of them, matte black and toothed, turning in oiled silence broken only by their own contact, descending into a dark that had no bottom he could see. The broken plating slid down into that gap and was taken. There was no crash. The metal simply went in, and thinned, and stopped existing.

Niko clawed up the slope on hands and knees, got one hand over the lip of the doorway, and hauled himself through as the floor behind him tipped past forty degrees.

He lay on level plating, chest heaving, and watched the doorway seal itself with a soft pneumatic sigh, as though the whole thing had been an administrative procedure.

The hum dropped back to its resting pitch.

He lay there a long time. When he could sit up, he pulled out the paper and read it again, because it was the only thing in the world that belonged to him.

SEVENTH. 418302.

"All right," he said to the empty corridor. His voice was steadier now. "All right. You move. Fine. You told me first. That crackle — that was a warning."

He thought about that. The crackle had come, and then he had turned in a circle, and then the walls had started. How long between? He replayed it, and found that he could replay it, precisely: the crackle, the flicker, the pitch climb, and his own breaths in between. Nine breaths. Maybe a minute and a half.

Ninety seconds. A minute and a half of warning before the world rearranged itself.

He stood, and looked left, and looked right, and discovered something else about himself. He knew the way he had come. Not vaguely — exactly. He could see it laid out behind his eyes like a drawing on glass: the eighty-meter run, the left branch, the high chamber with its four levels of walkway, the water panel eleven paces past the second junction, the arrows, the T. He could rotate it. He could look at it from above.

It was the first thing he had liked about himself.

"Okay," he said. "Then let's go see what's left."

He walked into a corridor that had not existed twenty minutes earlier, and began, without knowing it, to make a map.