The best fingerprint powder in the world, Dilly's old instructor used to say, is whatever's in the kitchen.

The Thornquist kitchen was very well stocked. She went through the pantry in under a minute and came back with an unopened tin of cocoa, a soft pastry brush, a roll of clear packing tape from the drawer of useful things, and the black lacquered tray from the top of the dresser. She dusted the contract's cover page in the light of the window with the delicacy of a woman icing a cake in a hurry. The brown powder caught in the ridges of the smudge and bloomed into a whorl: a loop with a small scar through the lower left side, as if the thumb had once met a very thin knife.

"Is she allowed to do that?" Junie whispered to Sel.

"I have no idea," said Sel. "I am enjoying it enormously."

She lifted the print with tape and pressed it to a white index card, and wrote on the card in capitals: DRAWER, SIDEBOARD, 7:52 A.M. Then she turned and looked at the people in the room, and for the first time in fourteen months she felt like herself. Not the woman in the clip. The other one. The woman with a clipboard in a hotel corridor at four in the morning who could count the doors and the faces and the people most likely to bleed.

"Eight keys," she said. "Seven of them are living. I want those people in this room in twenty minutes. Nobody tells anyone why. Nobody is accused of anything. Tea."

"Tea," said Sel.

"With the good glasses."

It was a trick as old as the trade and beneath her, in a way, but it worked because it was polite. They came in one by one. Pascual, who had been on the gate, took off his cap at the door. Bettina Oyelaran-Hart, the house manager, a tall woman in a grey cardigan with the bearing of an admiral in retirement, took one look at the tray and said, "Mrs. Odessa never served tea in the kitchen. I will be mentioning this at the funeral." Eun-ji Paredes, the attorney, arrived with her coat still on and the harried look of a person who had been awake for thirty hours and billed for twenty of them. Ferdinand Okoro-Lund, the night nurse who had cared for Odessa through her last six months, a soft-spoken man in a rumpled polo shirt, stayed near the door and held his tea in both hands as if someone might take it. Margit came last, and stood very straight at the end of the table, and did not take her glass until Dilly looked at it.

"Drink," said Dilly. "Sit. Put the glass down when you're done. Don't wash it."

The glasses were the clear heavy kind that took a print like wax. She let them talk. Eun-ji complained about the draft, Bettina about the cook, Pascual about nothing. When they had gone, the glasses sat in a row on the tray, seven of them, each one a small clear confession. She put on cotton gloves from the cleaning cupboard. She dusted. She held the white card beside each one, the way a person holds a dress up against a window.

Pascual's glass: a long oval, no scar. Bettina's: nothing like it. Eun-ji's, Ferdie's, Margit's: the shape of a kind of life, nothing in common with the scar. Sel's was close, but the whorl turned the wrong way.

Then Junie's glass.

She did not need to hold the card up. The loop was right there in the cocoa, and through the lower left side ran the thin white scar.

"Junie," Dilly said.

The girl was sitting on the counter with her sneakers on the cupboard door and a cardamom bun going cold on her knee. She looked up, and her whole face rearranged itself in stages, like a building being demolished in slow motion.

"Oh no," she said. "Okay. Okay, so. Before anything. It's not what it looks like."

"What does it look like?"

"Like I'm the leak." She slid off the counter. "I'm not the leak. I mean, I am a leak. But not like a mole. A normal leak. A dripping tap. Can I explain?"

"Please," said Sel, in a very small voice.

"Eun-ji texted me at like five this morning that the draft was done and it was in the drawer, and Sel's always saying I should read everything before it gets signed because I catch typos, so I came down to read it, and I read it, and I found two typos. Two. 'Consort' was spelled 'consert.' And then I was so stressed, because, like, a contract about a fake marriage, it's a lot, you know? And I had to tell someone." She said this very fast and without breathing. "So I put it in the group chat."

"Which group chat?" Dilly said.

"My friends. The Five. It's me, Kenzie, Sunday, Ottoline, and Pim. We tell each other everything. We have a rule: nothing leaves the chat. It's like a vault."

"It is exactly like a vault," said Sel, faintly, "if the vault is made of wet paper."

"I didn't put names! I said 'my boss is getting married for a year and the girl's mum's laundromat debt gets wiped.' That's all! I said 'my boss.' I swear on my phone." Her eyes filled. "Pim works at Ardent. In the call centre. She's not even, like, a person, she's a voice on a headset. She said she wouldn't tell anyone. She said 'omg that's so romantic.'"

The kitchen was silent. Bettina set her cup down on the saucer with a click like a sentence being passed.

Dilly took off the gloves. She looked at the girl for a long moment, and the old professional calculation went through her head: a leak was a leak, and a leaker was a liability, and the right thing, by every rule she had ever been taught, was to escort Junie out of the building. But she looked at the damp, appalled face and thought about herself at twenty-four, all the things she had told people because she wanted to be told they were good.

"Phones," she said.

"What?"

"Everyone in this house, from today. Phones in a box at the door. Work phones are issued. I'll set them. You don't discuss Sel, the Close, the house or me, with anyone, even the Five, even if Pim cries."

"Dilly, I'm so sorry, I would literally never—"

"You would, though," said Dilly. "That's why I'm saying it. You're twenty-four. You wanted somebody to tell you it was romantic." She heard her own voice and did not stop it. "It's a very human thing to want. You still can't do it with my life."

Junie nodded, hard, twice. Then she did the bravest thing Dilly had seen all morning, which was to say, "Okay," in a small clear voice, and go to the front hall, and put her phone in the box.

Sel was looking at Dilly with an expression she could not file. "You're going to be a terrible person to lie to," he said.

"I know," said Dilly. "I put it in the contract."

But something was still wrong. She stood over the card on the table, with the cocoa-dusted whorl and the scar, and felt it the way you feel a stair that isn't there. The print was Junie's, and the print explained the leak. It did not explain the smudge. A smudge, in her experience, is what a finger leaves when it has touched a surface that was already dirty.

She took the contract from the drawer, lifted the cover sheet in the window's grey light, and tilted it. Under the cocoa, along the left margin, so pale it might have been a shadow, ran a short line of blue-black marks: a thumb-width edge of ink, laid down a little above the staple. She pressed her nose almost to the paper. The ink had a slight metallic shimmer in the angle of the light, and a smell, faint and dry. Not printer toner. Older.

"Margit," she said. "What does the vault stamp look like?"

The Vault Clerk, who had been standing very still at the end of the table, did not move. "I beg your pardon?"

"The stamp. The one you use to witness the Close."

Margit crossed to the table. She did not touch the paper. She leaned and looked, for a long time, and when she straightened her face had gone the colour of the cocoa tin's lid.

"It is a blue-black iron-gall ink," she said. "Made to Mrs. Odessa's formula by a stationer in the old town. There is one pad in the city. It is in the vault on Merchant Street, in a locked drawer, to which there are two keys." She breathed. "One is mine."

"And the other?"

"The other," said Margit, "was buried with Mrs. Odessa's instructions. In a sealed envelope, in the safe in this house." Her eyes flicked to Sel. "That envelope has not left the safe since she died."

Sel had gone grey again. He went to the door of the study without a word, with Dilly right behind, and she watched him spin the dial on the safe with a hand that shook only on the last digit. The door swung open.

The envelope was there. It was sealed with red wax and Odessa's signet.

He lifted it. It was light. He turned it over. The flap under its seal was unmistakably lifted along one edge. He tilted the envelope over his palm, and nothing fell out, because there was no key in it at all.