The tongue was the worst of it. Not the pain, which was a bright clean thing she could have filed under ordinary, but the taste, iron and old coins, and the way it stayed in her mouth while she brushed her teeth in the staff toilet behind the lift at ten past five in the morning.

She spat into the sink and watched the water. Pink, then clear. She counted it, because counting was what she had: six rinses. Two exits from this room, if you counted the vent, which she did not, because she was thirty-three and not a cat.

Then she took the glove off.

She had meant to do it quickly, like pulling a plaster, but her hand did not look like a hand that wanted to be looked at quickly. The bleaching had climbed. Yesterday it had stopped at the wrist bone. Now there was a margin, a soft line like the edge of a watercolour wash, an inch up the forearm where the skin stopped being brown and became the colour of an overexposed photograph. She could see the grain of it. She could, if she tilted her wrist under the strip light, see through the pale to the vein, and through the vein, very faintly, to the tiled wall behind.

She flexed the fingers. They answered a fraction late, the way a bad video call answers.

"Noted," Zee told the mirror, and the mirror, to its credit, only lagged by half a beat.

The knock came at 5:40. Three knocks, evenly spaced, then a fourth after a pause, which was Rui's way of apologising for the first three. She pulled the glove on with her teeth and opened the door.

He was holding two paper cups and a flat black case the size of a bread board, and he looked as though he had slept in a chair, which he had; she had seen him in the lobby wing-chair at three, folded up like an umbrella. His headphones were round his neck. He had a crease on his cheek from the chair's piping.

"I come bearing a hot drink," he said, "and also evidence. I'm not sure which you'll want first. The drink is mostly hot water. I couldn't find the good tea."

"Evidence of what?"

"Do you want to sit down?"

"No."

"Then I'll say it standing, which is worse." He lifted the case an inch. "I left the recorder running. When I went to the lobby with you, last night. I clipped the little stereo pair to the lamp by the post boxes and I pressed record before the lift went down, and I didn't tell you, because I knew you'd say no, and because it's the only thing I know how to do in a room I don't understand. Listen to it." He winced. "I mean. I listened to it. It's the best recording I've ever made and I'd like to throw it into the harbour."

Zee looked at the case, and at him, and at the strip of dark corridor behind him, where the lift sat with its doors open and its little display glowing. She did not like that it was open. She did not like that she had to think about whether she liked it.

"Bring it in," she said.

The staff room was seven feet by nine. There was a camp bed, a kettle, a locker, a laminated fire plan she knew by heart, and now Rui Takahashi-Menezes sitting on the end of the bed with his knees up near his chest, setting a small silver recorder on the locker lid and plugging in a pair of earbuds that he then, after a moment's thought, did not hand to her.

"The headphones rule," he said. "Not a rule yet. A suspicion. I don't want it going into your ear unless you've got something to hold on to. Give me your good hand."

"They're both going to be the good hand in about a week."

His face did something complicated. "Zee."

"The left one's fine. It's cosmetic." She gave him her right hand. His palm was dry and warm, with a callus from a lifetime of gripping the edge of faders. "Play it."

He didn't use the earbuds. He turned the little speaker on, down low, so the sound came out thin and close, like a voice on a telephone line from a long time ago.

First, room tone. She knew it at once: the particular hum of the lobby at night, the lift motor, the cold-cabinet in the parcel room, the faint tick of the brass clock over the lift. Then a long stretch of nothing she could have sworn was silence, except that Rui reached over and turned the gain up, and the nothing became something. Breath. A great many people breathing, shallow and patient, in a space where nobody was. Feet shifting on wet tile. A cough that was not a cough but a sort of throat-clearing from a century ago. The soft hush of a queue.

"That's it," Rui murmured. "That's the eleven minutes. I can hear the whole room settle in. Listen to the reverb. It's not this lobby's reverb. The tail's too long. It's a bigger room, with a wooden ceiling. That's the Office. It's laid over our room the way a transparency is laid over a map."

"You're doing the thing."

"I know. I can't stop. It's very, very good."

On the recording, a man's voice said, in Portuguese, flat as a ledger: "Next."

Zee's good hand closed on his. He didn't pull away.

There was a long gap. On the file she heard her own steps cross the lobby, and her own voice, low, saying something that was probably a name, her great-grandfather's, because there was a second voice in answer, gravelly, brimming with a carpenter's patience, and she found she could not listen to that part. She looked at the fire plan. Rui moved the playhead without a word. The fine hairs on his forearm had stood up.

"Here," he said. "This is two fifty-eight."

The clerk, closer to the microphone than before: "Name."

A beat, in which the whole queue seemed to lean.

And then a woman's voice, quite near, quite calm, with the gravelly Lagos-by-way-of-Bahia vowels Zee had grown up with and spent two years training out of her phone voice, said: "Zainab Oyelaran-Pereira."

Nothing in the room moved. The kettle ticked as it cooled.

"I didn't say that," Zee said.

"I know."

"I bit my tongue. I was bleeding. I did not say that."

"I know. I was on the stairs from three to the lobby, I saw you. You didn't open your mouth." He swallowed. "The mouth on the recording is about two feet to the left of where you were standing. And it's not breathing out. Everyone breathes in before they speak, even if it's tiny. This one doesn't. It's all consonants and no air. Zee. It's the oldest trick in dubbing. It's a voice laid in with no body behind it."

"It's the double."

"It's your voice in her mouth." He said it very softly. "I think she took your turn."

The next sound on the file was the clerk's pen, scratching. A tiny, dry, patient sound. She counted its strokes without meaning to. Eleven.

Then: "Where from?"

And the recording stopped, not with a click but with a sort of exhalation, as if the thing had held its breath until it was out of road. The display on the little recorder said 02:58:11 and then, as they watched, the digits began to flicker and bleed, and the screen went white from the edges inward, the way a photograph goes in a fire.

Rui snatched his hand free and took the device in both of his. "No, no, no, come on, you old girl." It was already hot. He pressed the heel of his palm to the casing, as if he could hold the file in. A thread of smoke came out of the speaker grille, thin and sweet, like burnt sugar. He dropped it on the camp bed and it lay there ticking, and the little silver case turned the colour of a bruise.

"That was my teacher's," he said, to nobody. "Nineteen eighty-one. It survived a flood and a customs officer."

"Rui."

"It's fine. It's a thing. It was a thing." He was holding his hands out in front of him as if they were somebody else's. They were shaking. "I made a copy, anyway. There's a copy on the laptop, I did it at four, I always do. It'll be there. It has to be there."

It wasn't, she knew. She knew it the way she knew the sound of a safety coming off. She did not say so.

"I'm sorry," she said. It came out wrong, small and formal, a thing she would say to a client who had stubbed a toe on the car door.

He looked up. His eyes were very tired and very kind and for a second, she thought, quite angry, though not at her.

"Don't," he said. "Don't take this one. It's mine. I pressed the button."

"It's my voice."

"It's a recording of your voice that you didn't make, of a thing I chose to record. If you want to share it, we can share it. Fifty-fifty. I'm told that's how people do it." He wiped his mouth. "Okay? Fifty-fifty?"

She found, to her irritation, that her eyes were stinging. She looked at the fire plan until it stopped.

"Fifty-fifty," she said.

They drank the hot water. Neither of them mentioned that the kettle had never been turned on.

When they came out into the lobby, the dawn was putting its first flat grey light along the glass, and the brass clock over the lift read 6:02, and the damp footprints were gone, the whole column of them, as if the floor had licked itself clean. Only the last one remained, at the desk, the small bleached print of her left foot, dry now, dead white, the colour of her hand.

She did not look at it. She walked around the desk the long way and sat in her chair, and Rui went to the lift.

The display above the doors had been showing the same thing for two days: a neat little line of white text, PENDING: 2.

It wasn't showing that now.

"Zee," Rui said, from the lift.

She came round the desk again. She stood beside him, shoulder to shoulder, the two of them squinting up at the small amber screen like people at a departures board in a country they had no visas for.

It said:

PENDING: 3

GUS B-O. 3A. 7 NIGHTS. PIP N-V. 6C. 30 NIGHTS. Z. O-P. 0B. 1 OF 3.

"One of three," Rui read, out loud, in the careful tone he used for error codes. "That's the questions. Name, where from, whom do you serve."

"I know what it is."

"It doesn't have a day. For you. There's a number for Gus, and a number for Pip, and for you it just says what's been done." He turned his head, the good ear toward her. "It doesn't know when to call you in, because you haven't finished. It's waiting for the other two."

Behind them, at the front desk, something small and dry went tick on the tile, like a heel being set down.

Zee did not turn around. She counted, instead, the way she had been taught, slowly and from the top: one exit, two exits, her own breath, his breath. The lift. The glass. The clock.

"Rui," she said. "Is your hearing aid in?"

"I don't have a hearing aid. You know I don't."

"Then tell me what you hear."

He was quiet for a long moment. The lift whirred, behind its doors, for no reason.

"Someone's put the pen down," he said.