He did not let go of her wrist until she stopped swaying, and then he let go all at once, as if he had remembered a rule about it.

"Stand there," the stranger said, and pointed with his stylus at a spot on the landing. "All of you. In a line, if you can manage it. Shoulder width apart. I need to see each of you separately."

Nobody moved.

Suzu felt the silence behind her like a weight. Four sodden teenagers, shivering on a stone stair in the middle of a glowing sea, and a tall gray-skinned man with a waxed ledger who had just said the word "registered" as if it meant something she should already have understood. She could hear Nana's teeth chattering. She could hear Haruto, very softly, begin to say something and then think better of it.

"Do as he says," Suzu said, and was surprised at how ordinary her voice sounded. "Slowly. Nobody run, nobody shout. Miyu, Ren, Nana, Haruto. Line up."

They shuffled into a ragged row. The man watched them do it with his head slightly tilted, and his stylus began to move. He did not look down at the page. His eyes went from face to face, one, two, three, four, and with each look the stylus made a small dry sound against the ledger, like a mouse in a wall.

"Sakane Miyu," he said, without being told. "Hoshina Haruto. Tachibana Ren. Fujisawa Nana." He paused. "Your friend called you by name in the water. All of you. I was close enough to hear. I do not need to ask again."

Haruto's mouth fell open. "You were watching?"

"I was waiting. The old gate is not permitted to open. When it does, an Auditor attends." The stylus stopped. "I am the Auditor. My name is Sael Dunmarrow, third rank. I will be handling your registration."

"Your name," said Ren sharply, "is not the thing I'm worried about."

"No," said Sael. "I imagine not."

His gaze moved back to Suzu, and held. "You are the one they follow."

"I'm the president of our club," Suzu said. "Arimura Suzu. If you have questions, you can ask me. Please don't speak to my friends as if they're, as if they're items."

"They are not items. They are entries." He seemed to find nothing unusual in the distinction. "Each of you will receive one. It is a courtesy. Without an entry, you could not be fed, housed, or protected, and the tide would have taken you by morning."

"Is that a threat?" Ren said.

"It is a tide table."

Haruto laughed, a small, startled, hiccuping sound, and clapped his hand over his mouth. Sael looked at him for a long moment, and the clear inner lid slid across his eyes and back again. Whatever he had been about to say, he did not say it.

Suzu drew a breath. It was the one she used before club meetings, the one that said: you are the person who is holding the room.

"Mr. Dunmarrow," she said.

"Sael is sufficient. Rank is for the register."

"Sael. I'd like to understand the terms before we agree to anything. Where are we? What is this place called? How long will this registration take, and what happens afterward? Will you send us home?"

"Four questions." He tucked the stylus into the spine of the ledger. "I will answer them in order. This is Kethari. Its people call themselves the Kethari, and the sea that surrounds the tower is the Low Sea, and you are on the southern landing of Ninth Tower, which is under the jurisdiction of the Office of Audit. Registration takes one hour if you cooperate. Afterward you will be given lodging and a guardian. And yes." His eyes flicked toward the sky, toward the drowned sun. "The gate will open again. It opens on a cycle. When it does, you will be sent through, provided your entries are complete."

Suzu had been writing it down.

She had been writing it in the air, with her finger, against her palm, because her notebook was gone, and she realized it only when she looked down and saw a row of invisible tally marks. Something clenched in her chest. She curled her hand into a fist.

"When," she said. "When does it open again?"

"The next window is calculated for the seventh tide of the cold season. That is, in your reckoning, roughly nineteen days."

"Nineteen days," Nana whispered.

"At home," Miyu said slowly, "if the gate works like a thing with a period, and this is a, this is a different, there could be a time ratio. We could be gone for an hour and it's a month here. Or the reverse."

"There is a ratio," said Sael, and his tone sharpened a fraction, as though she had struck a note he had not expected. "It is not constant. I would not rely on it."

Miyu looked at Suzu. Suzu looked at the ledger.

"Tell us the rules," she said.

Sael did.

He spoke without notes, in the same clipped, even voice, and he did not stop for questions and did not skip a clause. Outsiders arriving through the gate must be recorded within one tide of arrival. Recorded outsiders were permitted to live within the Ninth Tower district but not to leave it. They were not permitted to work, to trade, or to carry any tool that could alter water, stone, or light. They were not permitted to form attachments. He said this last word in exactly the same tone as the others, but something in the way he said it made Suzu look up.

"Attachments," she repeated.

"Binding relationships. Marriage, adoption, apprenticeship, oath of service. It is a standard clause." He did not look at her. "Outsiders have no standing to enter into a contract. It prevents complications at the time of return."

"That's a strange thing to put in a rule book for strangers who fell out of the sky."

"It is the first thing the rule book was written to prevent."

He had said it quietly, almost under his breath, and it did not sound like something he had meant to say. Suzu filed it away, out of long habit, in the place she kept things she could not yet explain.

"One more provision," Sael went on, "concerns the guardian. Each party of outsiders is placed under the supervision of a single Auditor. The Auditor is responsible for the party's conduct, lodging, and safe return. To simplify the record, one member of the party is designated representative. The representative is placed under the personal guardianship of the Auditor. The other members are lodged in the district and report through them."

There was a pause.

"In other words," Ren said, "you pick a hostage."

"I do not pick. The party does." Sael's pale eyes moved along the line, and came to rest, quite precisely, on Suzu. "Though in this case I do not believe it is a difficult choice."

"No," said Haruto, and then, much too late, tried to soften it. "I mean. She's the president. It's her thing. It's, you know. She does the counting."

"I noticed," said Sael.

Suzu felt the heat climb up the back of her neck. She had been counted. She had, she realized, been watched counting, over and over, the whole way up from the water, and this man had been standing on a stair in the evening light and keeping a tally of her tally.

"I accept," she said. "On one condition. The others stay together. They do not get separated, they do not get moved without my knowledge, and I can see them every day."

"That is not a condition. That is a request."

"Then I'm making it as a request."

"It is outside the regulation."

"Then please explain to me exactly where the regulation says they can't."

For the first time his stylus paused, hovering above the wax. The membrane slid across his eyes and went away. "Clause seven," he said, slowly. "Sub-clause two. Parties may be lodged in separate quarters at the Auditor's discretion. It does not specify distance, frequency of contact, or manner of supervision."

"So there's a gap."

"There is a lack of specification. It is not the same as a gap."

"Is it different enough that you'd refuse?"

He studied her. It was not a rude look. It was the way a mathematician looks at a proof that has just gone off the page. "No," Sael said at last. "I do not believe I would."

Suzu felt, to her own surprise, the corner of her mouth try to rise. She caught it before it happened.

"Then we have an agreement," she said.

"We have a provisional understanding." He wrote something down. "Do not mistake one for the other. Provisional understandings can be withdrawn."

"I'll keep that in mind."

"Do. I will, for what it is worth."

The sun, or whatever it was, had lowered itself another hand's breadth toward the sea. The light was turning the color of weak tea. A long way off, across the water, a bell began to ring, slow and deep, the kind of sound you felt in your ribs more than you heard.

Sael looked toward it, and for the first time something like unease crossed his face. It was gone almost before she saw it.

"We have less time than I would like," he said. "Come. I will complete the form while we walk."

The stairs led up through an archway into the tower's lowest dry hall. It was a long cool room with a vaulted ceiling and tall arched windows set low in the walls, so that the sea lay level with the sills and the water-light moved in rippling nets across the floor. Benches ran along the sides. The air smelled of salt and old stone. Somewhere, very faintly, someone was humming a tune Suzu did not know.

They were given towels. They were given them without ceremony, a stack of coarse gray cloth that Sael set down on a bench and then stepped away from, as if the gesture were an administrative formality he would rather not witness. Nana wrapped herself up to her chin. Haruto, after a hesitation, handed one to Ren, who refused it and then took it anyway.

Suzu did not take one. She stood at the center of the hall with her wet hair dripping onto her collar, and watched Sael lay the ledger open across a stone table and begin to fill in the form.

"May I see?" she asked.

"No."

"It concerns me."

"It concerns an entry," said Sael. "It will concern you when it is finished."

She waited. He wrote. His handwriting was beautiful, compact and uniform, and he never once crossed anything out. At one point he stopped and looked up at her and said, without preamble, "You said your friend asked you something in the water. At the moment before the surface."

"Nana?"

"You let go of something. A bound sheaf of paper. It was floating. You had reached for it twice and then you did not."

Suzu's throat tightened. "My notebook."

"You were counting. You were counting aloud, in the water, before you saw the sheaf."

"I was not," she said. "You couldn't have heard that. Not underwater."

"I did not hear it. I watched your mouth." He returned to the ledger. "Three, four, where is five. Then you stopped, and you gave up the pages, and you took the girl."

There was nothing in his voice. It was a reading, not a remark. Yet Suzu had a sudden, dizzying sense of having been seen all the way through, as if some crucial piece of herself she thought was hidden had turned out to be printed in large letters on her forehead.

"You remember all of that," she said slowly.

"I remember everything." He said it the way another person would say they had brown hair. "It is a Kethari trait. In my case, a somewhat pronounced one."

"That must be exhausting."

His stylus stopped. For a long moment he did not move. Then the inner lid slid across his eyes, slowly, and slid back.

"No one has said that before," Sael said.

And then, as if the sentence had been an error he needed to correct, he lifted the ledger and turned it to face her.

"Read this," he said. "Out loud. For the record."

She took it. The page was thick and cool, the wax slightly tacky under her thumb. The form had been filled in a column at a time. Five names. Five ages. Five points of arrival. At the bottom, a single line had been left for the guardian's declaration, and it had already been written, in the same careful hand.

"Guardian," Suzu read, and her voice dropped. "Sael Dunmarrow, Auditor, third rank. Ward. Arimura Suzu, representative, eighteen years of age, birth recorded at" She stopped. "You haven't asked me where I was born."

"I will. It is not yet entered."

"Then why is there a blank?"

"Because I did not wish to enter it incorrectly."

She looked up. He was standing very still, with his hands folded behind his back like a student about to be examined.

"Continue," he said.

Suzu looked back at the page. "Ward. Arimura Suzu. Representative. Under the supervision of the Auditor until the date of return. Registered as yours."

She stopped.

Her own voice, saying those three words, had gone strange. Not louder, not softer, just somehow too close, as though the room had narrowed to the space between her mouth and his. She felt the heat arrive in her ears before it reached her face.

"It is the standard formula," said Sael, a fraction too quickly.

"I'm sure it is."

"It does not indicate anything beyond custody. It is a legal term of art."

"I said I'm sure."

"The form requires it."

"I understand, Auditor."

He fell silent. A drop of water ran down the side of Suzu's neck and into her collar, and she was acutely, ridiculously aware of it. Neither of them looked at the other. The silence lasted three or four seconds, which was far too long.

"There is one further clause," he said, in a stiffer voice, "that I am required to read to you. For completeness."

"Go ahead."

"Clause nine. Binding." He had not looked at the page; he recited it from memory, eyes fixed somewhere above her shoulder. "An Auditor may, at his discretion, accept a registered outsider into permanent guardianship. Such an outsider is thereafter deemed a resident, with the right to pass the gate in either direction. It is a formality. It has not been invoked in forty years, and I do not expect it to be invoked again."

"Why would anyone do that?" Haruto asked from the bench, interested in spite of himself.

"No one does," said Sael. "That is why it is a formality."

Suzu thought, with a sudden odd clarity, that it was the first thing he had said all evening that was not entirely true. She could not have said how she knew. Perhaps it was the lid, sliding across his eyes just as the word left his lips. Perhaps it was the way his fingers had tightened on the edge of the table.

She signed. There was a stylus for it, and her name looked small and crooked in the wax next to his.

The others were processed in turn, one at a time, behind a low screen, while Suzu sat on a bench with a towel around her shoulders and watched them go. Each emerged looking slightly stunned. Nana came out clutching a card of pale shell the size of her palm, with her name incised on it in a script Suzu could not read and could somehow understand. Haruto's was the same. Miyu's. Ren's. They held them like tickets to a train that had no schedule.

"What happens now?" Ren asked, and for once the sharpness had gone out of his voice. He sounded his age.

"You will be taken to the lodging house on the east quay," said Sael. "It is dry, warm, and clean. You will be fed. You will report through your representative."

"And her?" Nana said, in a tiny voice. She was looking at Suzu.

"She will be lodged in the tower." Sael did not look at Suzu. "Under my supervision."

Nana's face crumpled. She did not make a sound; she simply turned and put her arms around Suzu's waist. Suzu held her. Over the top of Nana's head, she saw Haruto look at Sael, then at her, then at Sael again with an expression of enormous, private speculation.

"It's all right," Suzu said, into Nana's hair. "It's a short walk. I'll see you tomorrow morning. First thing. I'll be at the quay at eight."

"You promise?"

"I promise." She heard herself say it, and she wrote it, mentally, in the margin of a notebook that was lying somewhere at the bottom of a sea she could not find again. Promise: Nana. Eight o'clock. Quay.

A boat came for them, a long low flat-bottomed thing poled by a silent, gray-skinned woman in a hooded coat. One by one the four climbed in. Suzu stood at the edge of the landing and watched them settle, and counted them. She could not stop. One, two, three, four. The woman poled away from the stair, and the boat slid out into the glowing channel, dark against the water, getting smaller.

Haruto turned in his seat and gave her an enormous, ridiculous thumbs up, which she would have found more reassuring if his hand had not been shaking.

She took the empty space in her chest, folded it carefully, and put it away.

"They are in no danger," said Sael beside her. She had not heard him come. "The east quay is a quiet district. The lodging mistress is reliable."

"I know," Suzu said. "You'd have said if it weren't."

He turned his head. "You assume that."

"You said you'd answer my questions in order. And you did. You even corrected yourself when you were off by a degree." She watched the boat round the corner of the tower and disappear. "That's not an assumption. That's data."

There was a pause. It was a very small one. It might have been the longest pause of the whole evening.

"I need one more item for the record," said Sael. His voice had changed slightly, flattened, as if he were speaking from behind glass. "Your date of birth."

She looked at him. "You said you hadn't entered it. I thought the form was done."

"The form is done. The record is not."

"The fourteenth of June," Suzu said.

"Fourteenth. June." He repeated it once, in a murmur, as if turning it over in his mouth. "Eighteen years."

"That's what it says."

"It will do." He turned away, and she realized, with a faint, odd shock, that he had not written it down. His stylus had stayed in the spine of the ledger. His hands were empty. His eyes were on the sea.

She followed his gaze, and for a long moment neither of them said anything. The last of the sunlight lay across the water in long copper threads. Out beyond the tower, a bell tolled again, deep and slow. Far below the surface, in the dark, something large and pale turned over once and was gone.

Suzu hugged the towel closer. She was shivering, she realized, finally and all at once, a deep helpless tremor that began in her jaw. She clamped her teeth and tried to will it away.

Something heavy and warm settled around her shoulders.

She looked down. It was a coat, a pale high-collared coat, edged in navy. It still held the heat of another person's body. It smelled faintly of salt, and of something clean and dry and cool, like a page.

"The rule is that outsiders may not be left to chill," said Sael, without looking at her. He had stepped back to stand with his hands behind him. He was in his shirtsleeves now, narrow-shouldered and straight. "It is not a kindness. It is a regulation."

"I know," said Suzu.

She did not give it back.

Behind them, at the foot of the stairs, a small figure lingered in the shadow of the arch, a boat-hand who had stayed behind to tie up the line. As Suzu turned to follow Sael up the stair, a hand tugged at her sleeve from the dark, and a voice breathed in her ear. It was Haruto, who had somehow slipped back off the boat for one last ridiculous farewell, and who now stood on the bottom step with his teeth still chattering and his eyes enormous.

"Madam President," he whispered. "Don't turn around. Just listen."

"Haruto, you're supposed to be in the boat"

"He never wrote anything down. Not once. Not your name, not mine, not any of ours. Not a single word, the entire time, except the stupid form." His voice shook. "And he knew everything. Everything we said. Think about that."

Above them, at the head of the stairs, the Auditor of Ninth Tower stood in the gathering dark and waited for her with his hands folded behind his back, and did not turn around, and did not need to.

Suzu pulled his coat tighter around her shoulders and began to climb.