The green notebook went into the safe in the library on Sunday morning, and Sienna did not open it.

She wanted to. That was the difficulty. She stood in front of the little steel door at the back of the shelves, with the lamp turned low and the morning light just beginning to show gray at the edges of the curtains, and turned the brass key on its cord between her fingers. It was a lovely object. It might have been made for her. It was the exact weight and size she would have chosen, with the exact color of leather, and the only thing in the whole room that she wanted less than to touch it was to throw it in the sea.

She laid it on the second shelf, beside a stack of old shipping almanacs, and shut the door, and spun the dial. She did not know whether she was being careful or ridiculous. Matteo, standing at the window with his bandaged hand tucked into his jacket, had watched her do it and said nothing at all. When she turned, he only inclined his head, once, as one does to a colleague at a funeral.

"Marco will look at the lining," he said. "And the clasp. And the paper."

"It's only a notebook."

"Yes." A pause. "So was Troy a horse."

She almost laughed. She went and sat at the long table instead, with the six green ledgers and the blue notebook in front of her, and Marco's envelope.

It was there at her place when she came down. A plain brown packet with the flap tucked in, and her name on the front in his square careful pencil. Inside lay a single typed sheet and four photographs, small and glossy, the edges still faintly curled from the drying line. She spread them out on the blotter and read the sheet twice.

Helena Roux had been in Carrow.

There was no mistaking it. Marco had gone over every inch of the thing with the thoroughness of a man crossing a minefield. A railway ticket, first class, stamped on the fourth of October at the north station, ten minutes past seven in the morning. A receipt from the Hotel Carrow Imperial for five nights, signed at the desk in a clear upright hand. The programme of a medical conference held in the municipal hall on the fifth, sixth and seventh, with the name of a Dr. H. Roux listed among the speakers, and a note from the organizer, who had been telephoned, to say that she had given her paper on Thursday morning and been the last to leave the reception. A return ticket on the evening of the eighth, from the same station.

She had not been in the house on the sixth of October, when the glass was sterilized for the second time. She had been four hundred kilometers away.

Sienna put the sheet down.

"So it wasn't her," said Matteo, from the window.

"It wasn't her hand." Sienna touched the first of the photographs. It showed a page from a spiral-bound log, the one that had hung on a chain beside the autoclave, Marco having copied it by night with a small camera and a great deal of patience. October the sixth. Cycle two. Glassware, two pieces, crystal. A hundred and thirty-four degrees, twenty minutes. And at the end of the line, in neat blue ink, the two initials: H.R.

"It looks like hers."

"It looks exactly like hers," said Sienna. "That's what worries me."

She got up and went to the shelf where the staff files were kept. Mrs. Venn, in forty-one years of service, had saved every paper that had ever crossed the threshold of the villa. In the second drawer, in a grey folder labeled MEDICAL, there were vaccination cards, and old prescriptions, and three or four letters on the clinic's notepaper, each signed with a firm black H. Roux that had been written, over eleven years, for the household of the Bellandis. She laid six of them out in a row on the table, beside the photographs, and drew her little canvas roll of tools toward her.

She had brought them from the lab: a pair of fine steel tweezers, a pocket magnifier no bigger than a coin, a small brass ruler marked in tenths of a millimeter. She sat down. She angled the lamp. And with the stillness she used for every careful thing, she bent over the page.

"May I watch?" Matteo said.

She did not look up. "You'll be bored."

"I assure you I won't."

"Then you may sit. But not on this side. You'll block my light."

He came round the end of the table and took the chair on her left, a little behind her, and she forgot about him almost at once.

It was her favorite kind of work. She had never been able to say why. It was not like the great grim business of toxins, with its hazards and its graphs. It was smaller and quieter, a matter of the eye. She laid the magnifier over the first initial and let the world shrink to the width of a coin: the blue ink, the faint soft furring of it where it sank into the paper, the tiny glitter of a spot where the nib had paused. An H. A full stop. An R.

"Forgers copy the shape," she said. She did not say it to him exactly. She said it aloud as she would have said it to herself, working, in the long silence of a basement at night. "That's all anyone can do. They trace the outline of the letter, the slant, the height, the loop. They get the picture of it right. But a hand isn't a picture. It's a motion. It has a rhythm, and a speed, and a place where it lifts. You can't copy that, because you can't see it. You can only see where it ended up."

"What does Helena's rhythm do?"

"I'll show you."

She moved the magnifier to the vaccination card, and then to the letter, and then to the third. Each H. Roux was a quick, upright, impatient flourish, set down in one movement. She traced it with the tip of the tweezers, not touching the paper, an eighth of an inch above the ink. "See the join between the H and the R? There's no break. She writes her name like a woman signing for a parcel, in a single pull. The pen never leaves the page. And here, at the foot of the R, a tiny flick to the right, always the same, always on the last stroke. A hook, the width of a hair."

"And the log?"

She moved the glass back.

She was quiet for a time. The lamp hissed. A clock ticked in the hall. When she spoke, her voice was lower.

"There's a lift. Between the H and the R. Here. You can see where the ink thins, then thickens again at the start of the next stroke. Somebody took the pen off the paper for a fraction of a second. And there's no hook at the end. It stops clean." She sat back. "Whoever wrote this was drawing a picture of Helena's initials. A very good picture. They were so careful with the slant that they forgot to be quick."

"Then it was a forgery."

"It was a good one. It would pass anyone who wasn't looking."

"But you were looking."

"I'm paid to." She rubbed her eyes, and found that her hands were trembling very slightly, the pleasant exhausted tremor that comes after a long hour of fine work. "Mrs. Venn kept every scrap, bless her. Without that, I'd have had nothing to compare it to."

She waited for him to say something. When he did not, she turned her head.

He was not looking at the photographs.

He sat a little behind her left shoulder, with his bandaged hand in his lap and his good hand resting on the edge of the table, and he was looking at her. It was not the look he had worn on the cobbles of Pier Four, or in the cold basement corridor, or across the ballroom. That one had been guarded, patient, full of care. This was none of those things. His face was quite undefended. His dark eyes were soft and very bright, and the line of his mouth had gone gentle in a way she had seen only once before, at the foot of a flight of stairs. He looked like a man who has been listening to a piece of music he knew by heart and has just heard a note he had never noticed.

She felt the heat start in her throat and climb.

"Stop that," said Sienna.

"I'm sorry."

"You're not."

"No," Matteo agreed. "Not really."

She put down the tweezers. She folded her hands in her lap, because they had begun, once again, to do something foolish. "What are you thinking?" she said. It came out sharper than she meant. It was a counterattack, pure and simple, the only one she could think of, and she knew it as she said it.

He did not hesitate. That was the thing about him, she thought, with a bitter little ache. When she asked him a direct question, in a clear voice, in the quiet of that room, he told her the truth. It was the only vice she had ever found in him that she could not forgive.

"I was thinking," said Matteo, very quietly, "that I have never in my life seen anyone look at a sheet of paper as you do. As though it might confess." His eyes did not leave her face. "And that I would like, once, to be looked at like that."

The lamp hissed. A coal shifted in the grate.

He heard himself. She saw him hear himself. The color left his face in a rush, and came back twice as strong, and he straightened in his chair as if he had been struck.

"That was not," he said, "a rule-one remark."

"No," said Sienna. She found she could not breathe properly. "It wasn't."

"It was a rule-two remark. Which I may not have the right to make."

"You asked me what I'd like in the library with the door locked," she said. It was absurd. It was not at all what she meant. "I mean. I asked you. And you answered. That's what the rule's for."

"Is it?"

"I wrote it," said Sienna. "I should know."

He made a small sound, very close to a laugh. The silence that followed was not a bad one. It had a warmth in it, and a kind of astonishment, as of two people who have both stepped out onto the same ice and found, to their surprise, that it held.

She turned back to the table. She picked up the tweezers again. Her hands were not quite steady, and she did not trust her voice, so she used the only instrument she had.

"We need to see Helena," she said. "With these."

"Yes."

"Tonight, if she's in. She told me she'd nothing to hide. I'd like to see her say it to a photograph."

"I'll have Marco bring the car round."

He stood. She felt him go, and did not look up. At the door he paused, and she heard him draw a long careful breath, and then the faint sound of the latch.

She stayed where she was for a moment longer with her eyes on the little glass. The lamplight swam. She found that she was holding the tweezers so tightly that the steel had left a white line across her thumb.

The clinic annex stood dark and glass-walled among the pines when they came to it at eight that evening, with a single lamp burning at the back.

A gray light had gone out of the sky an hour before. Now the garden was blue and still and very cold, and the cypresses had turned to black columns against a field of pricked stars. The gravel crunched under their feet. Beside her Matteo walked half a pace behind, in a dark overcoat, with his burned hand in his pocket and his eyes on the lighted window. At the corner of the hedge, a short way off, Marco had stopped his car and put out its lamps, and stood beside it like a man who had been left to guard the end of the world.

The door was unlocked.

She went in first. The white room was empty. The lamp on the desk had been shaded with a green cloth, and a single cup of tea steamed beside the blotter. The freesias on the sill had been replaced by a bunch of dry gray lavender. In the back room, through the open door, the great steel autoclave sat squat and silent on its counter, and the spiral book hung from its hook on a short chain.

Helena was sitting in the white chair behind the desk.

She was not in her coat. She wore a plain gray dress with a cardigan over it, and her sleek dark hair, for the first time since Sienna had known her, was not quite smooth. A strand had come loose at the temple. Her hands lay flat on the blotter. Her gray eyes were very large, and rimmed with a faint dark shadow, and when she lifted them to the door they did not seem surprised.

"I wondered when," she said.

"Dr. Roux." Sienna did not come any closer. "I'm sorry to come in without an appointment."

"You needn't be." A faint dry movement of the mouth. "I put the lamp on. I thought, if she comes at all, she'll come after dark. People who want the truth always do." Her gaze moved past Sienna, and settled on Matteo, in the arch behind her. It stayed there for a long moment, quite still, as though she were reading something written very small on his face.

"Mr. Bellandi," she said at last. "You look tired."

"I am," said Matteo.

Sienna took the packet from her bag. She did not hurry. She laid out the four photographs on the desk, one by one, in a neat line, and beside them the six old prescriptions, and the card, and the letter. She laid the little magnifier on top of them, like a weight. She did not say anything. She had learned that from Dr. Pryce, in the first year. If you put the evidence on the table and keep quiet, the silence will do the work.

Helena looked at the photographs for a long time.

Her hands did not move. She did not touch the paper. Her whole face seemed to be drawn very tight, as though someone had stretched a cloth across it, and when she spoke, her voice came from a long way down.

"That isn't mine," she said.

"No," said Sienna. "I know. There's a lift between the H and the R. And no hook on the last stroke."

Helena closed her eyes.

It was a small movement, but it was all that was needed. Something in her, held rigid for a very long time, gave way, quite quietly, the way a long-stretched rope gives way, strand by strand, until the last one parts. When she opened her eyes again, they were wet. She did not touch them. She sat very upright in the chair, with her hands on the blotter, and Sienna saw that they were shaking.

"I was in Carrow," she said. "On the sixth. I'd have been glad if anyone had troubled to ask me."

"I have the receipts."

"Of course you do." The ghost of a smile. "He told me you would. Marco, I mean. He telephoned on Friday. He was very civil. He is always civil." She drew a breath that rattled faintly in her chest. "It's the third time, you understand. This isn't the first. Since March, somebody has been signing my name. I found two prescriptions in the dispensary book in the spring. Two, for a sedative I had not written. I thought it was an error. I thought, I'm tired, I'm overworked, I've forgotten. I tore out the pages and I said nothing." Her mouth tightened. "And then the log. I would not have noticed that, but for you."

"Who?" said Sienna.

"I can't tell you."

"Dr. Roux."

"I can't." It was almost a cry. She pressed the back of her hand to her mouth, and took it away again, and it was shaking. "You don't understand. If I say a name in this room, I'll be dead by the weekend. It is not a figure of speech. I have thought about it every night since you walked in here, and I have never been more certain of anything in my life." She looked at Matteo. "Not because of him. Please believe that. Not because of you."

"I believe you," said Matteo quietly.

"Do you?" A thin cracked sound that was nearly a laugh. "You've never trusted me. Neither has she. That's very sensible. I should not trust me either."

Sienna did not move. She had seen this before, once, in a basement room at two in the morning, on the face of a technician who had made an error she could not bring herself to name. It was not guilt. It was something much older and much worse. It was fear that has been carried for a long time in silence and has turned, in the end, into a kind of dreadful courtesy.

A telephone rang.

It was a sharp electric trill, in the corner by the cabinets, and all three of them started. Matteo's hand went to his pocket. He took out a small black instrument, looked at it, and said in a quiet voice, "Marco." He turned half away. "Excuse me. One moment." He walked to the glass wall at the far end of the room, with his back to them, one hand pressed to his ear, and she heard the low rumble of his voice and the faint, thin buzz of the answer.

Helena leaned forward.

She did it so swiftly that Sienna had no time to prepare. Her hand shot out across the blotter and closed on Sienna's wrist, cold and dry and hard as iron. The gray eyes had gone wide, and very bright, and her voice dropped to a whisper so low that it hardly stirred the air.

"Three years ago," said Helena. "He came to me. He asked me, as a favor, to teach him how to copy my hand. For something else entirely, he said. A joke. A surprise. I thought nothing of it. I was flattered. I sat with him for an hour, over the clinic tea, and showed him how I turn an R, and the little hook, and where I lift the pen. And he laughed and thanked me and said he'd practice." Her fingers tightened. "He was a very good pupil."

Sienna's heart had begun to go very slowly, and very hard.

"Who?" she breathed.

Helena's eyes lifted. They went past Sienna's shoulder, over the white tile, to the tall figure at the glass wall. They rested on his back for a single long second. And in that second Sienna saw something pass across her face that was not fear, and not guilt, and not anything she had a name for.

It was a kind of terrible, protective pity.

"No," said Helena. She let go of Sienna's wrist. She sat back in her chair, quite upright, and folded her hands, and her face closed over like a door. "I have said too much. I am sorry. I should not have said any of it."

"Helena."

"Dr. Roux, please."

The latch of the glass door clicked. Matteo came back across the white floor, in his dark coat, with the telephone in his hand. He looked from one face to the other. His own was careful and perfectly composed, and she saw a fine line of tension at the corner of his mouth.

"Is everything in order?"

"Entirely," said Helena. Her voice was cool, and quite steady, and quite her own. "Mrs. Bellandi and I have been discussing a matter of professional courtesy. I think we are finished." She rose. She picked up the four photographs, squared them against the blotter, and held them out to Sienna in one hand, with a small formal inclination of the head. "I shall have the log removed from the autoclave. I'll deliver it to Marco in the morning. If it is any use to you."

"Thank you," said Sienna.

"You are very clever," said Helena, very low. "I told you so. I hope, for your sake, that it is not a fatal quality."

They went out into the cold garden.

The stars had come out thick and white above the pines, and the gravel crackled with a thin skin of frost. Behind them, in the long glass wall of the annex, the green-shaded lamp had been put out, and the room lay dark. Marco's car stood waiting at the corner of the hedge with its door open and its engine idling. Matteo walked beside her in silence for twenty paces. Then he stopped, quite suddenly, on the path.

"I did not hear all of it," he said.

"No."

"She spoke to you. I saw it. I was at the window, and the line was bad, and I kept my back turned. I thought it was kinder." He looked at her in the starlight. "Clause seven. You may tell me, or you may decline. But I'd like to hear it, if it's something that bears on you."

She was grateful to him, at that moment, with a quick fierce wave that nearly undid her. She had been trained since girlhood to hold her cards. She had spent a year, in a second life, hoarding every scrap of a secret she could not share. And here was a man in a dark coat on a frozen path who had stood with his back to a whispered conversation, on purpose, so that she might be spared the burden of having to decide whether to tell him.

She told him.

She gave it to him as she would have given a result, plainly, in order. Three years ago. A request to be taught how to copy a hand. A joke, a surprise. An hour over tea. A very good pupil.

"A man," said Matteo.

"She said he. She did not say who."

"And she looked at me."

Sienna said nothing.

"She looked at me," said Matteo, "when she said it. Didn't she? Before she stopped." His voice was very quiet. "I could feel it, through the glass. As one feels a draft."

"Yes," said Sienna. "She did."

He stood quite still. A little wind moved in the cypresses, and a faint cold glitter ran across the frost.

"I have never asked Helena Roux to teach me anything in my life," he said. "I give you my word. I can't prove it. I can only say that I have never learned to write in any hand but my own." He drew a long careful breath. "Which means either that she meant someone she was afraid to name, and looked at me because I stand beside the one she's afraid of. Or that someone has gone to a great deal of trouble to have a woman say, three years from now, in a quiet room, that a certain man asked her for such a lesson."

"A rehearsed accusation," said Sienna.

"Yes."

"It would be a very clever thing to do."

"It would be exactly the thing." His voice had thinned with a cold, patient anger that was nothing like the heat she had seen in the kitchen. "Someone has been preparing for this a long time."

She turned it over in her mind. She turned it over twice, slowly, the way she turned over any result that did not sit properly in the light. And as she did so, something else rose up behind it, whole and cold and entirely clear.

"The card," she said.

"Sienna?"

"The card under the ribbon. In your father's hand." She took a step toward him. "You said there were very few people alive who could have written it. You said it was a signature. And now there's a log in the clinic with initials copied so well that they would have passed anyone who wasn't looking." Her voice was shaking. "Whoever signed Helena's name learned how to do it from Helena. Three years ago. An hour over tea. And whoever wrote *Drink to a long life* in a dead man's writing didn't learn that in a night either."

It was the stillest she had ever seen him.

It was a stillness like the bottom of a well. He stood in the middle of the frozen path with the starlight on his face, quite white, and did not blink. She watched the thing she had said travel across his features, slow and terrible, from the eyes to the mouth and back again. She saw him remember a card, and a pocket, and a long slanting upright hand in black ink. She saw him remember that the man who had written it had been dead nine years.

"It is one person," Matteo said. He said it so softly that she could barely hear. "The same hand. The same pupil. It is one man who learns how other people write, and he has been learning for three years."

"Or longer."

"Or longer." His eyes closed. "God."

She put out her hand and laid it flat against his chest, on the dark cloth of the coat, without thinking. She felt under her palm the hard quick beat of his heart. It was not steady. She had never touched him without asking, since the night of the rules, and she did not take it away.

"We'll find him," said Sienna.

"I know."

"We'll find him before the fourteenth of September."

"I know that too." He covered her hand with his gloved one, lightly, as if it might frighten away. "I am only," said Matteo, "very much afraid."

It was rule four. She felt it go through her. She had written it down herself in her own small hand, and he had said it aloud on a frozen path with the stars above him, the first time either of them had ever kept it.

"So am I," she said.

They stood together in the cold for a long moment, with Marco's engine idling softly at the end of the hedge and the whole sleeping garden spread out around them, silver and black. Neither of them said another word. Then he drew her hand from his chest, and held it, and they walked back to the car without speaking, side by side, with a quarter inch of frosty air between their arms.