The hospital corridor smelled of floor polish and boiled rice, and Haeseul knew it so well that her feet found the way without her.

Third floor, east wing. Past the nurses' station with its crooked poster about hand washing. Past the vending machine that hummed a half tone flat, and the row of orange plastic chairs bolted to the wall, and the window at the end where, if you stood close to the glass, you could see a slice of the harbor between two apartment blocks. She had walked this exact corridor for four years. It was not the same hospital, and the ward was a different one, neurology instead of oncology, but hospitals were all built by the same patient hand, and her body had decided that it was home.

She stopped at the door of room 314 and did not go in.

Through the narrow glass panel she could see the bed. Han Gyeol lay on his back with the blanket drawn to his chest and one arm resting outside it, an IV line taped to the inside of the elbow. His hair had been combed by somebody. His face was clean and slack and young, and the monitor above him drew its small green hills, steady and even, hill after hill after hill. He looked like a boy taking a nap in the middle of a school day. He had looked like that for sixty hours.

"He is stable," the doctor had said, that morning, in the corridor, with a tablet held against his chest like a shield. "Everything is normal. The scan, the bloods, the EEG. I will be honest with you, Pharmacist Yeon, I have never seen a case like it. His brain is doing exactly what a sleeping brain should do. It simply will not wake." A small, helpless lift of the shoulders. "We will keep running tests."

She had thanked him. She had said all the right things. And she had stood in the corridor afterward with her hands in the pockets of her coat, where nobody could see them shake, and thought: you will not find anything, because there is nothing to find.

Her left sleeve had ridden up as she pushed the door. She tugged it down, quickly, over the two pale rings on the inside of her wrist.

"Haeseul-ssi?"

A woman was rising from the chair beside the bed. She was small and rounded and fifty or so, in a cardigan the color of weak tea, with her hair tied back anyhow and the creased, scrubbed look of someone who has been awake for three days and washed her face in a public toilet. It was Gyeol's mother. She had come up from the coast by the first bus on the morning after the ambulance, with a bag of dried persimmons and a rice cooker that she had been unable to explain, and she had not left the room since.

"Mrs. Han," said Haeseul. "Please, sit. I did not mean to disturb you."

"You are not disturbing." The older woman crossed the room in three quick steps and took both Haeseul's hands, and her palms were dry and warm and gripped very hard. "You are the one who found him. They told me. You were the one who called. I do not know how to..." Her mouth trembled. "He has talked about you so much. Noona this, Noona that. He says you are the best pharmacist in the city. He says you taught him how to hold a patient's hand."

"He taught himself."

"He says that you never once raised your voice."

"I raised it plenty," said Haeseul, and found, to her horror, that her eyes were filling. She blinked hard. "I am so sorry. I should have sent him home. He had been working too many nights. I saw that he was exhausted, and I let him go on, because we were short-staffed, and because..." She stopped.

"Because?" said Mrs. Han.

Because I did not want to be alone in the shop. Because I knew something was wrong and I told myself it was only the wiring. Because I was the one who brought it in.

"Because I was careless," she said. "That is all."

"The doctor says it is exhaustion. A kind of collapse. He says it can take a while to come out of."

"Yes."

"That is what it is?" The woman's eyes searched her face, black and bright and terribly hopeful. "That is what you think?"

It was so simple. It would have been the easiest thing in the world. A pharmacist, in a corridor, in a white coat, saying yes, Mrs. Han, that is what I think. And what Haeseul felt, in that instant, was not the weight of the lie but its familiar shape, the smooth, well-fitting, sensible shape of the words she had been handed for two weeks by a pair of dark eyes and a careful voice. I told you what I understood. She was holding it out to a frightened woman as gently as it had been held out to her.

"Yes," she said. "I think he will wake. I think he is only very tired."

Mrs. Han pressed her hand to her mouth. She nodded, rapidly, and sat down.

Haeseul stood a moment longer, looking at the bed. Then she went out into the corridor and walked as far as the window at the end, and stood with her forehead against the cold glass, and thought, quite clearly, in the cool cataloguing voice she used for dosages: that is what it feels like from the other side.

She had been so angry. She had been so righteous. And now she had stood in a hospital room and done the exact thing she had condemned, with no more excuse than that the truth was too large to hand to a tired woman at ten in the morning. It did not make her forgive Eunhae. But it moved something, a little, like a stone that has been resting in the same place for a very long time.

She went home at noon. She lay down on the bed in her clothes and did not sleep.

It was a curious sensation, by now. She was so tired that her bones ached. Her mind felt as if it had been packed in wet wool. She lay on her side with her eyes closed and her breathing slow, and every nerve in her body was perfectly, glassily awake, and when she opened her eyes again the light had gone from yellow to gray and she understood that four hours had passed in which she had slept for none of them.

She sat up. She took the green notebook from the nightstand and opened it flat on her knees.

She was a woman who believed in data. It was a conviction, and a refuge, and in the worst years it had been something very like a faith. A doctor could lie, and a family could be wrong, and a person's feelings could not be trusted for one minute together, but a number was a number, and if you wrote it down faithfully, it would tell you where you stood. She drew a line down the center of a clean page. On the left she wrote: BEFORE. On the right: AFTER.

BEFORE was easy. She had two years of figures. She turned back through the book and ran her pencil down the columns, and a small, quiet, perfectly mathematical horror crept over her as she read. 2h40. 3h10. 2h50. 3h20. A few nights at four. Once, at the worst of the winter after her mother died, a single terrible night of ninety minutes. She added them. She divided. Her average, over the last year, was three hours and five minutes, give or take.

It had never been good. She had always known it was not good. But as she looked at the page she saw something she had not seen before, something that the daily writing had hidden from her, as a single brushstroke hides the painting. It was not a sleeping pattern. It was a slope. It had been falling, slowly, almost imperceptibly, for two years, like the level of a tank with a slow leak.

She turned to the right-hand column. AFTER.

The night of the first new moon: no sleep, held in the shop. The day after: eleven hours, and no rest in it. The next day: four. The next: three and a half. A week of nights that had settled at barely above three, but with a difference, a new quality in the tiredness that she could not have put into numbers. It was not the old gritty wired exhaustion. It was thinner. It was like living in a house with all the furniture slightly moved, so that she kept bumping into the empty places where it used to be.

And the nights since. Two nights, nothing. Two nights, nothing at all.

She wrote the figures. She wrote a question mark. She underlined it.

What had been taken? She was a pharmacist. She understood pharmacokinetics, half-lives, dose-response curves. She knew that every substance had a cost that could be measured, if one only had the instruments. She turned to a fresh page and wrote, at the top, in firm capital letters: ASSUMPTIONS. Under that she wrote: 1. It takes sleep. 2. The amount is proportional to the strength of the draw. 3. The draw was larger on the second occasion, because I was not prepared and she was desperate. 4. It leaves a mark. 5. The mark has a number.

She stopped.

Twelve ticks on the first ring. Seven on the second. Nineteen in all. She did not know what it counted. But she thought, with the slow cold lurch of a held breath, that she could guess how to find out.

She took out her phone, and found the number written on the back of a repair ticket, and did not call it.

At seven, with the evening coming on and a pot of rice cooling on the stove that she had not touched, there was a soft knock at the door.

She opened it on the chain. A round face looked up at her from the landing, lit from below by a paper bag.

"I brought congee," said Oh Garam. "You do not have to let me in. But it is very good congee, and I will stand here and get cold if I must."

Haeseul unhooked the chain.

Garam came in like a small warm gale. She was in her gray cardigan, with the pocket hanging off, and her curls were coming down in the damp, and she looked at the bare room, the unmade bed, the open notebook, the pot of cold rice, with a single sweeping glance that missed nothing and said nothing. She set the bag on the table. She unpacked a covered pan, two spoons, a jar of pickled cabbage. She put the kettle on.

"Sit down," she said. "Eat. Then talk."

"You sound like her."

"I sound like everyone who has ever cared for anyone." She ladled out the congee, white and creamy and flecked with sesame, and pushed the bowl across. "I went to the hospital. I looked in on him. Do not be cross."

"I am not cross."

"His mother gave me a persimmon." Garam sat. She folded her hands on the table and her face, in the yellow lamplight, was tired and gentle and entirely serious. "He is not ill, Pharmacist. You know that."

"I know."

"It is a Keeper's sleep. It is a very old thing. It happens when a Hushed has been fed too long on one heart and then finds a door left open. It does not take them away. It takes them in." She paused. "There is a woman inside him. A very sad woman. She has gone to sleep in his dreams, and she will not leave unless she is asked, properly, by someone who knows the right way."

"Eunhae."

"It will take Eunhae. It will take the count, and it will take..." She did not say the word. She looked at the bruise-colored ring of the seal where it showed, a pale thread beneath the cuff of Haeseul's sleeve. "It will take you."

"I know."

"You are not obliged. I want you to hear me say that." Garam's voice was low. "I have said it to myself every night for three years, and I have never once believed it. Nobody is obliged. A person owes another person nothing at all. But there is a boy in that bed, and I think you are going to go anyway."

"Yes," said Haeseul. "I think I am."

"And I think you are going to ask her."

Haeseul laid down her spoon.

"I have been asking," she said. "I asked on the floor of the pharmacy, in front of the ambulance, with Gyeol lying there. She said she knew there was more. That is all she said. I have been sitting in this room for two days, doing arithmetic, trying to work out what a person can be asked to give without being told the price." She looked up. "You know what it is. You were there for the whole of it. Tell me."

Garam looked at her for a long time.

"I cannot," she said.

"Garam-ssi."

"I cannot, and I will tell you why. It is not that I would not. God knows I have wanted to. It is that I made a promise to the Baek women a long time ago, the old one and the young, and the promise was this: that the cost would be told by the Keeper herself, in her own voice, to her own anchor. It was Ongjo's rule. It was a good rule. She broke it with me, and she was sorry for it every day until she died, and it was the only thing she ever asked me to make right." Garam's eyes were wet. "If I told you, it would be a theft. It would be taking the thing from her that she most needs to give. She has to say it, or she is not the woman I raised."

"And if she does not say it?"

"Then you will leave. And I will not blame you." A little crooked smile. "I will make you congee, and I will not say a word."

Haeseul found that she was laughing, a little, and a little not. She pressed her knuckles to her mouth.

"What do I do, then?"

"Ask," said Garam. "Ask her. And if she does not answer, ask again. And again. And again." She reached across the table and covered Haeseul's hand. Her palm was warm. Her fingers, as they always were, were faintly cold. "She is not a liar, you know. She is only a coward. They are different things, and the second can be cured."

The letter had been waiting at the pharmacy for three days.

Haeseul went in at ten that night to cover the shift. She had told the manager, a bald, harassed, decent man named Mr. Pyo, that she could do it, and she had meant it, and when she stepped through the door and the bell rang and the fluorescent light came down over her, she felt such a wave of dizziness that she had to grip the counter. The morning pharmacist, a brisk young woman named Ji-yeon who was packing her bag for the night, looked up.

"Oh," she said. "Pharmacist Yeon. There was someone for you."

"Someone?"

"A woman. Short hair, gray jacket. She came in the morning after the ambulance, when we reopened. She would not give her name. She said you had left something here and that it belonged to you." Ji-yeon rummaged beneath the counter. "She said to give it to you and nobody else. I put it in the drawer. I am so sorry, I did not think. It has been such a strange week."

She held out an envelope.

It was an ordinary brown one, the kind sold in sheaves at the stationer's on the ground floor of Haeseul's building, with her name written across the front in a fine, upright, very careful hand. Something small and hard had been pushed into one corner. She did not need to feel it to know what it was.

"Thank you," she said. "You may go."

She waited until the girl had left. She waited until the bell had stopped trembling. Then she went to the stool behind the counter and sat down, and slit the flap with her thumbnail, and shook the contents into her palm.

The key came first. It lay in her hand on its faded red cord, warm from the paper, small and brass and worn pale at the bow. Then a single sheet, folded in three.

It was a short letter. She read it standing, because she found that she could not sit.

Haeseul,

I am not going to ask you to forgive me, because I have not earned it, and because you would be right to refuse.

I am going to tell you what I did. I knew the price was greater than I said. I did not know how much greater. I knew that sleep was taken and that it was not given back, and I told you it would be a thing you could recover from, because I was afraid that if I told you otherwise you would go. That is the whole of it. It was not an accident, and it was not a kindness. It was fear. I have been frightened for so long that I have forgotten the difference between protecting someone and using them.

There is more that I know, and I have not said it. I will say it. I am not going to promise you when, because I have broken enough promises, and I would sooner give you one that I can keep. But I will say it before you are asked to give any more than you have given already, and if I do not, you will be right to go.

The key is yours. It was always yours. I have not touched the shop door since Tuesday and I will not change the lock.

Whatever you decide about the boy, I will do it with you or I will do it alone, and I will not hold it against you either way.

I am sorry. It is a very small word for what it is for.

Eunhae

She read it twice. Then she folded it along its creases, and put it in the pocket of her coat, over her heart, where a repair ticket had once lain.

She did not cry. She stood under the humming lights with the key in her fist and a tight, aching, perfectly still sensation in her chest, like a held note, and she thought, I do not know what to do with this. She had been ready for a defense. She had been ready for an excuse, a long, persuasive, tender explanation, because it was in the nature of the people she had loved to explain. She had not been ready for a woman who wrote, simply, it was fear.

At half past midnight she shut the shop, and left Gyeol's replacement, a mild young man from the agency, in charge of the till, and walked up the hill.

She had not meant to. She told herself, at the corner by the temple, that she was only going for a breath of air. She told herself, at the top of the street, that she was only going to look. But the light was on in the back of Slow Hours, a thin gold bar under the blind, and her feet carried her to the door as though they had been doing it for years.

She did not knock. She unlocked the back door with the brass key, and it opened at once, as it had been made to, and she stepped through into the dark of the workshop with her heart in her throat.

Eunhae was at the bench.

She was sitting in the lamplight with her back to the door, bent over a mechanism, with a loupe in her eye and a pair of tweezers in her fingers. She was working. She was working with the slow, dogged, unseeing concentration of a person who has been working for a long time because stopping would be worse, and the whole room had the stale, rumpled, airless look of a place where nobody has slept. Plates stood stacked in the little sink. A blanket lay in a heap on the floor beside the bed. And the forty-one clocks ticked on, a trifle out of step, as if they too had lost the habit of rest.

Eunhae did not look round. She said, in a low, level, exhausted voice, without lifting her head, "The key is not on the latch. If you wanted me to come out and say something, I am afraid I do not have it."

"I have the key."

The tweezers stopped.

For a long moment the room was perfectly silent. Then, very slowly, as though she were afraid of what she would see, Eunhae set the tools down on the felt, and put her hands on the edge of the bench, and turned her head.

Her face was gray. It was the color of putty, with deep brown hollows under the eyes and the cheekbones standing out sharp as blades. She looked as if she had not eaten in two days. She looked ten years older than the woman who had laughed over a rose-flavored rice cake. And she looked at Haeseul with an expression so stripped, so helpless, so entirely without defense, that all the speeches Haeseul had been composing for three days fell out of her head at once.

"You are alone," said Eunhae.

"I walked."

"I did not think you would come."

"Nor did I." Haeseul crossed the floor, slowly, and stopped a pace from the bench. She held out her hand with the key in it. "I read your letter."

"Ah."

"I think it was the most honest thing anybody has ever written to me."

"It was not honest enough."

"No," said Haeseul. "It was not. But it was a great deal more than I had." She drew a long breath. "I have done some arithmetic. I should like you to listen, and I should like you not to talk until I have finished, because I will lose my place."

Eunhae nodded.

"I have been averaging three hours and five minutes of sleep a night for the past year. It has been falling. Since the first new moon it has fallen faster. I do not yet know how much of that is you and how much is me, and I do not think either of us does. I have a ring of twelve marks and a ring of seven, and I think they are a count, but I do not know what of. I have a boy in a bed who will not wake, and a woman asleep inside him, and I think that I can help, and that you cannot do it alone." She paused. "That is the sum. I am prepared to try one more time. One. To wake Gyeol. Under conditions."

"Anything."

"Condition one. It is a sip, not a draught. You tell me, before we begin, how much you mean to take, and you take no more. I do not care how desperate it becomes. If you are about to lose him, and the only way to keep him is to take the whole of me, then you let him go, and you tell me afterward, and I will make the decision myself."

Eunhae's eyes had filled. She did not look away. "Yes."

"Condition two. I say stop, you stop. Mid-count. Mid-word. I do not care."

"Yes."

"Condition three." Haeseul's voice had begun to shake, and she steadied it. "The thing that you know. The thing that you are afraid to say. You said you would tell me before I was asked to give any more. I am asking you to give more tomorrow night. So I think the time has come."

There was a silence.

Eunhae closed her eyes. Her mouth worked. For a moment Haeseul thought she would simply say it, there and then, in that tired room, under forty-one clocks, and she found that she was holding her breath, and that she did not know whether she wanted her to.

"I cannot," said Eunhae.

"Cannot."

"I mean, I cannot yet. I am not saying it to delay. I am saying it because I have lied to you once by hiding something, and I will not lie to you a second time by telling you something half-formed that I am afraid is true." She opened her eyes. "There is a thing I read in my grandmother's journal. I have read it a dozen times, and I understand the words but not the whole of what they mean, and I do not want to hand you my fear when I can hand you the fact. I need to find out whether it is a fact. Give me until the next dark of the moon."

"That is three weeks."

"Nearly three."

"Eunhae."

"I know." Her voice cracked. "I know what I am asking. I am asking you to trust me with the one thing I have just proved I cannot be trusted with. But I am promising you that I will tell you by the second new moon, whatever I have found. And I am promising that if you ask, before then, whether the cost is more than you can bear, I will answer that question truthfully and at once, as far as I know it."

Haeseul looked at her. At the gray face, and the burning eyes, and the hand pressed flat against the edge of the bench to stop it shaking. She thought of Garam. She is not a liar, you know. She is only a coward.

"Is it more than I can bear?" she said.

Eunhae did not answer at once. She looked at her for a long, long moment. And then she said, very low, with an effort that made the words come out like stones: "I do not know. I think that it might be."

The silence was complete. Even the clocks seemed to hold their breath.

"Thank you," said Haeseul.

"For what?"

"For not saying no." She closed her fingers over the key, and put it, with a small dry click, into the pocket of her coat, beside the letter. "That is the first time you have told me something that frightened you more than it frightened me. I find that I am able to work with it."

She went home at two. She did not go to the back room, though the door stood open and the bed was made. She said goodnight at the threshold, and Eunhae said it back, and they stood a moment looking at one another in the thin gold light, as people look who are about to cross a river and have not yet decided to get their feet wet.

At the corner of the temple she stopped, under the lamp, and took out the notebook.

She wrote the date. She wrote, under it, in a small neat hand: Agreed to one attempt. Conditions set. She has asked for three weeks and I have given them. I do not think she is lying. I think she is afraid. I think I am afraid too.

She stood for a time with the pencil lifted over the page. Then she wrote one more line, below the others, in smaller letters, and she looked at it for a long moment before she shut the book. It said: I do not want it to be the thing I think it is.

She did not show it to anyone. She walked down the hill in the dark with her hands in her pockets, and her pulse ticking quietly against the inside of her wrist, where nineteen small cold marks counted something she did not yet understand.