The silver saloon was already at the kerb outside number forty-one, its engine ticking as it cooled.

Sol killed the van's lights half a street away. For a second the four of them sat in the dark cab, Sol and Kaveh in front, Nadia and Liesel wedged in the back among the flour, listening to the rain start up on the roof like someone tapping to be let in.

"Third floor, sixth door," Liesel whispered. "The window's lit."

"Yes," said Kaveh. "I can smell him from here."

"Dov?"

"Cedar and cold tea and a very expensive soap." His nostrils flared. "And, under that, Saoirse. Calm. And a man in pain, who I take to be Bastian." He paused. "Nobody is afraid. That is unusual. In a room containing the Director of the Assay Office and a woman he has been surveilling for eleven years, I would expect fear."

"She makes a point of not having any," said Liesel, with the shadow of a smile. "It's the aphids."

They got out. Kaveh went up the stairs first, quietly, with Liesel two steps behind him and Sol bringing up the rear with her mop. Nadia was last, and she noticed, absently, that her hand had gone to the memory stick in her sock and stayed there, as though it were a lucky coin.

The green door of 6B stood open a hand's width. Light spilled out, and with it the smell of cocoa, and a murmur of voices, one of them low and pleasant and entirely at its ease.

"...of course, I'd never have knocked. I rang. I was admitted. It was most kind. I do apologise for the hour."

"I don't mind," said Saoirse. "I was awake. You've got a lovely voice, by the way. Has anyone told you? It's like being read to by a dentist."

Kaveh pushed the door.

The flat had not changed. The plants in the windows, the pinned drawings, the long table. On the doormat the tulips lay where Bastian had set them down. Bastian himself was sitting on a kitchen chair by the stove with an ice pack against his skull and a face the colour of putty, quite conscious, not at all comfortable. And at the table, in a pewter-grey suit, with a mug of cocoa in front of him and his hands folded as if at a christening, sat Dov Albrecht-Nwosu.

He looked up, and smiled with real warmth.

"Kaveh," he said. "And Liesel. And, ah." His eyes went over the shoulders of the two of them and found Nadia, and stayed. "And you. I did hope."

Nobody moved.

"Ms. Whitcombe-Nair was just giving me her recipe for cocoa," said Dov. "She adds a pinch of salt. I'd never have thought. Do come in, you're making the room feel crowded. Mr. Nkemelu-Frost, you may go home. Take a taxi. I'll put it on the department."

Bastian rose with a stiff groan, ice pack to his head, and edged round the wall like a man leaving a hostile church. He did not look at Nadia. At the door he paused, and said to the floor, "Sir, I didn't send it."

"I know you didn't, Bastian. I'm told you're very concise." Dov's gaze had not left Nadia. "Go home."

The door closed.

Saoirse, from her place at the stove, said brightly, "More cocoa?"

"Thank you, no," said Dov. "I find it keeps me up."

He stood, not quickly, and smoothed the front of his jacket. Up close he was bigger than she had remembered, broad and soft and warm-looking, with a fatherly stoop and the tired eyes of a man who had been awake for decades on other people's behalf. He took in the sight of them, the four of them clustered in the doorway: the auditor at the head, hands loose; the heir behind him; the courier with her mop; the chemist in the Brightline tunic.

"I'm not here to hurt anyone," he said. "I'd like that understood. I'm an old man, and I've never raised my hand to a living soul, and I've sat in this flat for twenty-three minutes with the only person in this room who has the slightest reason to be afraid of me, and she has offered me a biscuit." A glance at Saoirse. "I intend to leave her in peace."

"You've had her on a list for eleven years," said Liesel.

"I've had her *safe* for eleven years. It's not the same thing, I grant you, but it's closer than you think." He turned to Nadia, courteous, interested. "You're very quiet, Dr. Quispe-Halloran. I'd have expected you to say something sharp. Your father always did."

"You knew him."

"I loved him." The Director said it with such simplicity that the room caught. "We were at the university together. He was the cleverest man I ever met. He'd just discovered, at twenty-three, that he could not be read, and I was the first person he told. I told him it was a gift. He said it was a hole." He smiled. "He was right. I've spent thirty years proving it."

"You killed him," said Nadia.

"No."

"The doctor said you called him a loose end."

"Fenwick is a frightened man, and I'm afraid he says whatever will keep him on his feet." Dov's voice did not change. "Pablo had a stroke. I held his hand at the funeral. I did not kill Wren either, though I imagine you have decided I did. Wren fell. It was an accident and I have not slept properly since." He paused. "There are people in this city who would like very much for you to believe that the Registry is a murderer. It isn't. It's a machine for keeping us all inside the same truth. I built a good deal of it. I'm *proud* of it."

"The Tether pilot," said Kaveh.

"Ah, yes. My late-night reading." Dov inclined his head. "Kaveh, I wanted to tell you myself. I wanted to tell you on Saturday, at the table, with Liesel by your side, and I apologise for the order of events. Tether is a sensor. It reads a bond by chemistry, not by nose. It cannot be fooled by tea." A glance at Liesel. "Nor by cocoa. Within eighteen months, every Assay in the city will be conducted by a machine that cannot be bribed, drugged or charmed. The forgery trade will end. The bond will mean what it was always supposed to mean."

"And the scentless?"

"Are the control group. Without them, the machine cannot be calibrated." He opened his hands. "It's very dull work, and they are paid handsomely, and nobody is hurt."

"And if they refuse?"

"Very few do."

Saoirse said, mildly, "I did. Four times."

"Yes. And I left you alone, which is why you're here eating your own toast. I think I've been rather patient."

The silence stretched. Nadia found that her fists were clenched and made them open. The man in front of her had the voice and the eyes and the gentleness of the best teacher she had ever had, and he had just told her, in front of her friends, that her father was a hole.

"What do you want?" she said.

"Volume ten," said Dov Albrecht-Nwosu.

Nobody spoke.

"Pablo's last notebook. I understand Odile Ostergaard has it in a safe. She is a lovely young woman, and a coward, and she will not give it to me." He folded his hands again. "But she would give it to you. I need it, Nadia. You do too. Your father wrote down how to beat Tether. He understood the principle before the machine was drawn. He built a dose that makes a bonded pair read as *anything at all*. A counter-formula. He told me so, the week before he died. I think he meant it to be his revenge."

He turned to the door, adjusted his cuffs, and gave the room a nod, as courteous as a host at the end of a long and agreeable party.

"Bring it to me by Saturday," he said, "and I will take your name off the list. And hers." A glance at Saoirse. "And yours, Liesel, if you like. Or don't, and watch what the machine finds in the dark." He paused on the threshold. "Thank you for the cocoa, Ms. Whitcombe-Nair. It really was very good."

He went out.

Behind him, nobody moved for a long moment. Then Saoirse turned off the hob, took the mug he had left, rinsed it in the sink, and set it on the rack.

"Well," she said. "He's lovely. I hate him."

Liesel laughed, once, and then put her hand over her mouth, appalled. Sol sat down on the arm of the sofa and said, "I need a drink and a lawyer, in that order, and I don't have either."

Saoirse crossed the room and put her arms around Liesel from the side. Liesel leaned into her without a word, the way a tree leans when the wind has gone. Nadia looked at the table, at the ring on the wood where Dov's mug had sat, and was surprised by how steady her hands were.

Kaveh was standing by the window with his back to the room. He had not spoken since Dov left.

"Auditor," she said.

"I am thinking."

"Out loud would be fine."

"I am thinking that in the space of nine days, I have discovered that my mate is not my mate, that my Director is a murderer or a liar or both, that my colleague of six years is a collector of human beings, and that the only person in the city I can trust to tell me the truth is a woman I met in a lift and cannot smell." He turned. His face was white and quite composed. "I am thinking that I should like to hear your idea."

"I haven't got an idea."

"Liesel said it was a good one."

"Liesel has had a long night."

"Nadia." The name came out like a thing he'd practised. "Please."

She breathed in. She held it. She found that this was a corner she could not talk her way out of, and that she did not entirely want to.

"A bonded human takes on her wolf's scent," she said, to the table. "Within weeks. If I were bonded to a Registry auditor, I wouldn't be a hole in the room. I'd be a woman who smells like you. The Director's list could still have my name, but no one could pick me out on the street." She made herself look up. "It would also get rid of your problem. If you're bonded to someone else, Liesel can dissolve yours by consent, and nobody audits anything. It's a fraud. It solves everything. And I don't want you to say yes."

"Why not?"

"Because you'd say it for the same reason you do everything. Because it's correct."

Kaveh looked at her for a long moment.

"You are wrong about me," he said, "in an interesting way." And the phone in his breast pocket began to buzz.

He took it out. The screen lit his face from below. She watched him read, and watched the colour, which had only just returned, drain out of him again.

"What?" said Liesel.

"A notice from the Registry. Issued eleven minutes ago, by the Director's office." He read it aloud, in a voice from which all inflection had been scrubbed. "*In light of recent concerns, annual bond renewals for senior Registry staff are brought forward. Auditor K. Dastgheib and mate L. Ostergaard-Banda will attend Marrow House for verification on Friday at nine in the morning.*" He looked up. "That is in thirty-three hours."