Rook's notice came with the morning bread, and for the first time in twenty-one days Suzu was glad to see the old man's signature.

It was a single cream strip, folded in thirds. The formal review of the ward's effects, it said, which had been set for the fourteenth day, was deferred by order of the Senior Auditor, who had been summoned to the upper office on a matter concerning the gate. It would be reconvened after the window. The signature at the bottom rose in one long stroke, like the tail of a bird.

"Reprieve," Suzu said to the empty room. The word did not feel entirely honest, so she folded the strip in four and slid it into the inventory book beside the others.

The window was tomorrow.

She had known it for sixteen days, in the way one knows the date of an examination, as a fixed point at the end of a long corridor. Dusk ebb on the twenty-second day, plus or minus six minutes, from the copper wire and the slate and the girl who talked to her solder. Now the corridor had run out. Tomorrow at dusk they would walk to the Old Basin with everything they owned, and either the water would open or it would not, and either way, after tomorrow, there would be nothing left to prepare.

So she prepared.

She had called a full rehearsal for the fourth bell, on the steps of the east quay. Packs, rope, water, rations, Miyu's meter in its padded crate, the whole walk to the Old Basin timed from the first step to the last. She had written it all out the night before in four columns. She had made Haruto repeat his column back to her twice. She had checked the knots on the carrying pole with her own hands, and then, because the first check had felt too easy, she had checked them again.

There was a cup on her table when she left the tower, warm all the way through, with a slip tucked under the saucer. Fourth bell. I am required on the upper landing until the fifth. The cup is not a requisition. It is a cup.

She drank it on the stepping stones, with the sun on the back of her neck, and did not write that down either.

---

The east quay was bright and busy when she arrived, and her party was already assembled on the lowest step in a cheerful, untidy row.

Haruto had volunteered for the front of the carrying pole and was demonstrating, to nobody, how he would look under load. Miyu sat on the crate with her chin on her fist, turning the little brass cog at her collar between two fingers. Ren stood a little apart with his arms folded and his pack square on his shoulders, and had apparently decided to disapprove of the rehearsal in silence.

"Madam President," Haruto called. "We are present, packed, and in excellent spirits. I have also made a small flag."

"We don't need a flag."

"Everybody needs a flag."

Suzu opened the inventory book and uncapped the stylus. "Roll," she said, and began.

"Haruto."

"Here."

"Miyu."

"Here," said Miyu, without looking up.

"Ren."

"Obviously."

She made a tick beside each name, and her pen moved on to the fourth line, and stopped.

It did not stop for any reason. She simply wrote the first letter of the name, N, and then the stylus lifted, and her eyes went up from the page and travelled along the row of faces. Haruto. Miyu. Ren. The empty place on the step beside Ren, where a smaller person would have stood.

"Where's Nana?" she said.

"Reading the gauge," said Ren. "She said she'd be back by the fourth bell."

"What bell is it?"

Nobody answered. Across the water, from the tower, from the Office, from the market, the fourth bell began to ring, slow and deep, and Suzu counted the strokes with her whole body as she had counted everything for six years. One. Two. Three. Four.

She looked at the row again. She counted it again. Haruto, Miyu, Ren. Herself, which made four, and four was the number she had written at the top of the page in the first column, the number she had taught herself, in a pool, at dusk, never to be satisfied with.

She counted a third time, with her lips moving.

"That's three," said Haruto, more quietly than he usually said anything. "Suzu. That's three times."

"She's at the post," said Suzu. "She'll be at the end of the quay. We'll walk down."

She did not run. She walked, at a quick even pace, with the book against her chest, past the lodging house and the stall that sold dried eel and the stack of lobster traps at the corner, and her party followed her in silence. The gauge post stood at the very end of the quay, where the stone ran out into the water: an iron pole with a brass scale, a small flat rock for sitting, a slate hung from a hook. The slate was in its place.

The rock was empty.

Suzu took the slate down. Nana's handwriting ran across it in neat, round columns, hour by hour, in the number-script the shell cards had taught her. It was the most careful record she had ever seen on a child's slate. Every line was dated. Every figure was underlined. The last entry was timed at the third bell, and under it, in the same careful hand, she had ruled the next row, ready, the way you set a place at table for someone who is coming.

The row was blank.

---

She had thought she was ready for it.

That was the strangest part, afterward. She had been preparing for twelve years. She had made a whole life out of lists and ticks and second counts, a small iron fence of procedure around every person she loved, and she had been so certain that when it finally came she would know what to do. She would be calm. She would be quick.

Instead the quay went away.

There was a field, bright and green and wrong. Wind in tall grass. A rope bridge hung above a gully, and the sign at its foot said CLOSED in letters she had read and decided were old. A girl's voice, thin and far, calling her name from the wrong side of the trees, Suzu, Suzu, I can't find the path, and herself standing on the path with the route sheet in her hand, thinking, I checked it. I checked it. I checked everything.

"Suzu."

She was looking at her own hand. It was shaking so hard that the stylus rattled on the slate. Her thumb was working at the cap, open and shut, open and shut, and she could not make it stop.

"It's my fault," she said.

"Suzu"

"I assigned the gauge. I gave her the post. I put her out here alone, every hour, for ten days, and I thought it was a kindness because she liked the work, and I never walked down to check whether the sluice was fenced. I never even looked at it. I should have looked at it." Her voice was climbing. She could hear it, and could not stop it. "I counted. I counted every time. I counted and I still"

"Yes," said Ren.

He had come up behind her. His face was white, with two spots of color high on the cheekbones, and his voice was very low and very flat. "You count and you still lose people. That's what I keep thinking. You stand there ticking us off like a, like a shopping list, and you still lose us."

"Ren, man," said Haruto. "Not now."

"When, then? After?"

"He's right," said Suzu.

It came out of her very quietly, and everyone stopped. She heard it land. She felt it settle in her chest, cold and heavy and entirely familiar, like a coat she had been wearing for years and had only taken off for a little while.

And then, because she had no other tool, she did the thing she always did.

She closed her mouth. She breathed in through her nose. She felt her shoulders go square, felt her voice drop into the register she used for emergencies and the vice principal, and she turned the slate over in her hands and looked at her three friends with an expression she hoped looked like calm.

"All right," said Suzu. "Listen. Here is what we do."

Haruto's mouth, which had been open to speak, closed again.

"Last confirmed sighting, the third bell, at this post. It's now the fourth bell and some minutes. She cannot have gone far. We search in four sectors. Haruto, the east lanes and the market side, as far as the humped bridge. Ask everyone, even if they don't answer. Look at faces, not at the ground. Miyu, the customs house and the lodging house, every room, then the shed behind the cistern. Ren."

He flinched.

"The canal bridges," she said. "All four. Look under them. Look in the water, not on it. Look for anything that doesn't belong." She held his eyes. "I need you to hate me later. Right now I need you to search."

A long moment passed. Ren's jaw worked. Then, stiffly, he nodded.

"I'll take the post and the quay wall myself," she said. "Reconvene on these steps at the fifth bell, whatever you find. Go."

They went. Haruto ran, which she had never seen him do so fast. Miyu went at a walk that was nearly a run, with one hand clamped to her little brass cog. Ren went last, and he looked back once, and it was not the look of someone who had won.

Suzu stood alone on the end of the quay with the slate in her hands and counted the stones in the wall, because it was something to do.

---

"You have altered the schedule."

She did not turn at once. She knew the voice, and she knew, without looking, how it would sound: level, careful, with the faintest tension in the consonants, like a rope under load. She wiped her face with the back of her wrist and turned.

Sael stood three paces behind her with a folded slip of paper in one hand and the courier's satchel at his hip. He must have come down from the tower very fast. The hem of his coat was dark with spray, and his hair, which he combed with such discipline, had been blown across his forehead, and he had not corrected it.

"The gauge readings," he said. "They are transmitted hourly to the tower. It is a routine. The entry for the fourth bell has not arrived. I came to ascertain whether the party had changed the roster."

"No." Her voice cracked on it. "No. Nana's missing."

She waited for it. She had been waiting, in some back room of her mind, for fifteen years of her life: the small tightening of the mouth, the exchange of looks, the quiet thank-you-for-telling-me that was worse than any shout. She had her answer ready. It's my responsibility. I will take full account.

Sael said, "When was she last seen, by whom, and where?"

Suzu stared at him.

"The third bell," she said, after a moment. "Here. She was reading the gauge. Ren saw her last, when he brought her water. She was on the rock. She was fine."

"Did she appear distressed?"

"No."

"Did she mention an intention?"

"She, I don't know. I'll ask Ren."

"I have asked him. I passed him on the second bridge." He had stepped to the post and was crouching beside the rock, studying the stone. "He said she mentioned that the sluice at the head of the third channel had a, in his words, a stuck wheel. That she wished to see it. She regards faults in instruments as personal."

"The sluice," said Suzu. "I thought. I never thought of the sluice."

"There is no reason you should have." He did not look up. "It is not within the permitted district. It is two hundred paces beyond the boundary, on the old wharf. The Office never fenced it. I have noted this in two reports."

"They were filed," said Suzu, and her voice shook, and in the middle of everything something almost like a laugh came out of her.

"They were filed," Sael agreed. He touched the stone with two fingers. "Here."

She crouched beside him. On the wet flagstone at the edge of the quay, where the spray had not yet dried, there was a faint print: a small round heel, a narrow toe, pointing away from the post. Another beyond it, fainter. A third, at the lip of the steps that led down to the old wharf.

"She walked," said Sael. "She was not carried. The stride is regular. She was not running."

Suzu pressed the heel of her hand against her mouth. The relief came so hard it nearly folded her.

"It does not mean she is safe," he said, quite gently, and she nodded without taking her hand away. "But it means she was in possession of herself when she left. That is a datum. It is a good one."

He stood. He held out his hand to her. She looked at it. It was a perfectly ordinary gesture, offered with a perfectly blank face, and she took it, and he drew her to her feet, and let go as soon as she was balanced.

Nobody had ever asked her that. Not when. Not by whom. Not where. In all the years of her life, in every room where something had gone wrong, she had never once been asked a question that did not already have an accusation folded inside it.

"Thank you," she said, and it came out ragged.

"I have not done anything." He said it a little too fast. "I have asked for the facts. It is the procedure."

---

The old wharf had been abandoned for longer than the customs house. It lay at the end of a causeway no wider than a cart, past the last of the lodging houses, where the stone turned green and then black and the air smelled of rust. A row of iron bollards ran along the edge. Beyond them, in the shadow of a low arch, the water of three channels came together in a basin of dark, slow-turning green, and at its head, set into the old stone, was the sluice: a wheel the height of a man, with spokes as thick as her wrist, mounted on a frame of rusted iron.

The wheel was stuck. She could see that at once. It was turned a quarter-way and wedged, and a thin sheet of water was escaping round its rim and sliding down the stone in a glittering curtain.

On the lowest rung of the iron ladder beside it, caught on a splinter of rust, hung a small pale object.

Suzu did not hear herself make the sound. She only found that she was kneeling on the wet stone with the thing in her palm. It was a shell button, small and pearly, with four tiny holes and a scrap of gray thread still knotted through two of them. She knew it. She had seen it every morning of the last twenty-one days. It had been sewn onto the collar of a borrowed tunic by a girl who was clumsy with needles and who had insisted on doing it herself.

"She was here," said Suzu.

"Yes." Sael stood at the lip of the basin, with his back to her, looking at the three arches. "The tide turns at the sixth bell. It will be a flood, a high one. The moon is at the full of the larger. The three channels will fill from the sea inward, and the third, which is lowest, will fill first." He paused. "The third channel is the only one with a stair."

"A stair?"

"An old inspection stair. It runs down into the under-wharf, a network of drains and refuges built before the Office was founded. It is mostly flooded now. I have walked it. I do not remember a lamp in it in thirty years." He turned. "I believe she went down."

"Why would she go down?"

"Because it is a fault in an instrument," said Sael, "and she is Fujisawa Nana."

Suzu closed her fist around the button.

Across the water, the fifth bell began, and from the far end of the quay, small and distant, she heard Haruto's voice, hoarse already, calling a name into the lanes. The light had gone from white to gold. A long way off, past the arches, the Low Sea was drawing a deep breath.

"Tomorrow," she said. "The window opens tomorrow at dusk."

"Yes."

"And tonight the flood comes."

"Yes."

"Then we have until the sixth bell."

"We have until the sixth bell," said Sael, "to find her before the third channel closes. After that, I cannot say."

He did not say anything else. He did not tell her it would be all right. She noticed that, with a distant, shaky gratitude: that he did not lie to her, even now, even when it would have been so easy. He simply stood at the edge of the black water, with the evening wind pulling at his collar, and looked at the dark arch of the third channel the way she had once looked at a rope bridge.

She got to her feet. The button was a hard small thing in her fist.

Two hundred and fifty paces behind them, the gauge post stood with its blank row, ruled and ready. And somewhere under her feet, in the dark, a girl who had wanted only to mend a wheel was waiting for someone to come.