The engine was called Sabre, though it had never cut anything. It rode on Ines's back in a cradle of brass and cooling-wire, and it hummed when it was content, which was less and less. On the morning they entered the city that would not hold still, it was not humming at all.

They had come to map Oradia before the ministry declared it gone. This was the work: to walk a dying place and fix it to paper, so that when the water rose or the ash came down, there would be at least a record that streets had run here, that people had turned left at a certain corner every evening of their lives. Ines had mapped nine cities this way. Sabre had drawn every line.

"North gate," she said, and the engine ticked, and a nib the size of an eyelash began to move across the vellum stretched inside its chest. She felt the drawing through the frame the way another woman might feel a cat purring. It was the closest thing to company she had left.

The trouble began at the third turning. The map said the Street of Lamps ran straight to the river. The street disagreed. It bent, and where it bent there was a square that Sabre had not recorded an hour before — a fountain, dry, and around it houses with their doors standing open like mouths caught mid-sentence.

"You missed it," Ines said.

The engine's hum climbed and cracked. On the vellum, the nib hovered, trembling, and did not descend. I did not miss it, the needle-print stammered across the margin, in the cramped little hand it used for speech. It was not there.

She had been warned about Oradia. The surveyors who came back — not all of them came back — spoke of a place that revised itself, that grew a lane overnight and swallowed one by dawn, as though the city were a manuscript and something patient sat editing it. The ministry did not believe them. The ministry believed in ash and water and the slow honest deaths of things. It had sent Ines to draw a corpse and instead she had found a body still turning in its sleep.

They mapped anyway. What else was there. All that afternoon the streets moved under them like the deck of a ship, and Sabre drew and erased and drew again, and its cooling-wire ran hot enough to redden her shoulders through the leather. By dusk the vellum was a palimpsest, a hundred cities laid over one another, and none of them was the city they were standing in.

"Stop," she told it, at the edge of a plaza that had been a graveyard a moment before. "Stop drawing. Just look. Tell me what stays."

The engine went quiet in a way it never had. She understood, standing there, that she had asked it to do the one thing it was not built for. Sabre could record. It could not choose. Every line it had ever made, it had made because she named a direction and the world obliged. To ask what stayed was to ask it to decide which of the city's thousand faces was the true one — to prefer, to forget, to lie a little in the service of a larger truth. That was her work. It had only ever been her work.

And then, softly, the nib moved.

It did not draw the plaza. It drew a woman drawing a plaza — a small figure with an engine on her back, standing precisely where they stood. Around the figure it left the vellum blank, deliberately, gorgeously blank, and Ines understood that the blankness was the answer. This stays, the margin said. You, here, looking. The rest is weather.

She laughed, and the sound frightened birds she could not see. For nine cities she had believed the engine was the instrument and she the hand. Now it had drawn her into its own map and named her the fixed point, the one coordinate the city could not revise, and she did not know whether to feel honored or erased.

The ash began at full dark. It came down the way the surveyors had promised, fine and grey and warm, and where it settled the streets at last stopped moving, pinned beneath it like specimens under glass. Oradia was becoming a corpse after all. It had only wanted, she thought, to be seen turning before it went still — to have one witness who would not flatten it into a single tidy death.

Sabre hummed. It was, impossibly, content. On the last dry corner of the vellum it wrote a final line, and Ines had to hold the lantern close to read it, the ash already gathering in the creases of her hands.

Name the direction, it said. I will draw us out.

She looked at the map of herself, looking. Then she named a direction that was not on any street, and the engine, trusting her the way it had always trusted her, began to draw a road that had never existed, out of a city that soon no longer would.