"Dari," Dilly said.

It came out before she had decided to say it. The name had lived at the bottom of her mind for fourteen months, like a coin in a drain. Dario Fenwick-Mbeki: six-two, calm, a man who made coffee for the whole team without being asked and always remembered how you took it. They had worked three years as a pair. He covered the left. She covered the right. A principal in the middle, a stage in front, and the two of them at her shoulders like a pair of brackets.

"That's what I told her," said Priya. "I said, a man named Dario. The company's records said so too. He was on stage left, six feet from me, in a charcoal jacket. I never spoke to him. I never really looked at him. He wasn't the one I was watching." She let her eyes rest on Dilly. "Where is he now?"

"I don't know. He gave a statement to Calloway and Pryce the next morning. They told me he'd been very kind about it." The words were dry in her mouth. "He said he'd called out to me, and I hadn't responded. That I'd gone rigid. That he'd said my name three times."

"Did he?"

"I didn't hear it."

"No," said Priya. "I don't think you did."

The mist had thickened into a kind of fine rain. Somewhere inside the Ferrymen's Hall, a hundred voices rose and fell in the long shapeless murmur of a funeral turning into a party. Dilly stood with her back against the cold brick and felt the old shame come up through her like water through a floor, and with it something else, something underneath, slow and heavy, that had no business being there.

"Priya. What did Odessa say to you? After the question?"

"She asked what my security company logged for comms that day. Radio, earpiece, the lot. I said I'd have to check. I did. Hollowell had already done a forensic review of the event, because our insurers insisted. We'd recorded everything: the stage audio, the PA, the vendor's backup of the team channel. I never listened to the team channel. I'm not a security professional. I don't know what I'd be listening for." She reached into her coat and took out a small brushed-steel drive on a lanyard. "Odessa did. She said that when I found the file, I should give it to you, in person, nowhere near a computer you owned. She said you'd know when to listen."

Dilly looked at it. A piece of metal the size of a thumb. It might have been a key or a grenade.

"She sounds like she was a very difficult woman," Priya said, "and I liked her a lot."

"Everyone did. Even the ones who didn't." Dilly closed her hand around the drive. "Why bring it yourself? You could have couriered it."

"Because I wanted to see your face." Priya's mouth tilted. "And because I'm told you're getting married on Friday, and I don't send wedding presents by courier."

Dilly stared at her.

"Everyone is talking about it," said Priya. "I run a company that tracks how the town spends its money. Two hundred of your neighbours have bought a cheap white dress on Tally since Tuesday night. It's a trend."

She did not listen to it at the hall. She waited until the reception thinned, until Sel had been escorted three times to the same sofa and made to sit, until Bettina had wrapped a flask of broth in a napkin and Pascual had brought the car round. She waited until she had checked the back seat, the boot, the wheel arches, and the floor under Junie's feet. Then she got in beside Sel, took out her old wired earbuds from the lining of her bag, and plugged them into the little steel drive's adapter.

"What is that?" Sel said.

"A recording of the worst afternoon of my life." She said it without drama. "I'd like to listen alone. If that's possible in a car."

He looked at her for a moment. Then he turned, with perfect courtesy, to the window, and said, "Junie, would you be so good as to tell me everything you know about the trend in white dresses?" and Junie, who had been about to ask what was going on, gulped and began.

The drive had four files. She opened the last one, labelled TEAM_CH_BACKUP_0211.wav, and pressed play.

Static. A hush of wind in a headset, the squeak of a lanyard. Then a recorded voice she had not heard in fourteen months and had never expected to hear again: her own, thin and young and professional, saying, "Check. Check. Stage right ready." A man's voice, warm and slow, replying: "Stage left ready. Morning, Dil."

Dari.

She had to put her head back against the seat. It was so small a thing: the cheerful gravel of his voice, the way he said Dil, as if it were a toy he had been given. She listened to the countdown. The crowd noise rose. There was a woman on a PA reading out a sponsorship credit. Priya's voice rose, tinny and lovely, on the speakers, introducing the product. Dilly's breath was on the file, slow, steady, the breath of a woman doing her job.

She had known the clip so well she could have drawn it. In her mind, the next part was the vault over the rail, the hoodie, the arm coming up. But on the recording, before that, there was something else. A click. A tiny electronic click, in her left ear, the sound of a channel opening.

Then a voice said, in the earpiece, very close and clear: "Dilly. Hold."

She stopped breathing.

"Hold," the voice repeated, quietly, urgently, a man giving a quiet order he trusted to be obeyed. "Hold your position. It's a stunt. It's staged. Priya's team set it up. Hold."

Her own voice, at once, on the recording, almost a breath: "Copy."

The drive hissed. Then came the sound of a man shouting, the thump of a body on the rail, a woman's scream, laughter, the splat of a pie on a face. The sound of her own heartbeat, which the microphone had caught through the collar, going from sixty to a hundred and forty in the space of a second. And, at last, Dari's voice, loud and frightened, in the channel: "Dil! Dilly, move!"

She took the earbuds out. Her hands were shaking. She laid them in her lap, careful, as if they were glass.

She had remembered it. That was the thing. She had known all along, somewhere beyond the reach of the memory she kept filed, a murmur, a voice, a single word. For fourteen months she had told herself it was something she had made up afterwards. An excuse, the kind a failure builds out of nothing, a tidy little lie so you can stand up in the morning. Hold. Of course she had heard hold. Everyone who freezes hears hold. She had said so to the Calloway and Pryce investigator, and watched his face. She had said so to her mother, who had said nothing. And then she had stopped saying it, because nothing made you look guiltier than a defence.

I didn't flinch, she thought. I obeyed.

She put the earbuds in again. She played it again. And a second time. Listening, now, not for the words but for the voice, the way a bodyguard listens to a crowd for the single flat note.

It was Dari's. It was exactly, perfectly Dari's: the grain of it, the warm gravel, the slight upward lilt at the end of an order. It was the voice of the man she had worked beside for three years. And it was wrong.

She could not say how. It had no breath in it. That was the thing: a human voice speaking close to a mic has the small sounds of a body, the wet click of a tongue, the draw of air between sentences. This voice had none. It was smooth all the way through, like glass. And behind it, if she turned the volume up until the hiss roared, there was something else: a very faint, regular stutter every nine-tenths of a second, a tiny digital catch, like a heartbeat in a machine.

She opened the second file. VIDEO_STAGELEFT_CAM.mp4. It was a dull stationary shot, the kind a venue records for insurance, wide, high, a little blurred. She dragged the marker to the time stamp that matched the click. Zoomed in.

The stage. The podium. Priya small and bright in the centre. On the right, herself: a straight, dark figure with her hands clasped in front, her head turned, watching the room. On the left of the frame, six feet from the podium, in a charcoal jacket: Dari.

She watched his mouth.

The voice in her earpiece said, Dilly. Hold. And Dari, on the screen, stood with his lips closed, both hands folded, looking out at the crowd. He was not speaking. He was not wearing a mic. He had no finger on the transmit button. The voice went on, urgent, warm, instructing her to stand fast, and the man whose voice it was stood six feet away, calm, silent, watching her do exactly what the voice said.

At second fourteen, he turned his head. For the space of one frame he looked straight along the stage at the woman standing frozen on the right. His expression was not shocked. It was not frightened.

It was interested, the way a man looks at a clock.

"Dilly?" said Sel, gently, from the other side of the car.

She pulled the earbuds out. She was aware of Junie's sudden silence, of Pascual's eyes in the mirror, and of how very quiet a car can be. She looked at the screen, at the stopped frame of a calm man in a charcoal jacket, and she heard her own voice, flat and steady and entirely unlike her.

"Sel. I need to find out whether a voice can be made to say something the person never said."

"It can," said Junie, in a small clear voice, from the front. "It takes about forty seconds and a clip of the person talking. There are apps. It's a whole thing."

Nobody spoke.

In the rear-view mirror, Pascual's eyes met hers, and she realised that for the first time in fourteen months she was not looking at the face of someone who thought she had failed.