“My twins, my babies, they’re safe in here with me but she’s trying to unlock the door from the outside. She’s trying to take my babies, don’t you understand? Help me.”

Gideon caught Harper’s eye, shocked, sickened. He paused the recording.

“That poor woman,” he said. “She sounds terrified. But what needs cleaning up? It seems clear enough to me.”

“It’s not this bit. It’s towards the end. You’ll know when you hear it.”

They reached the hissing section and Gideon started to work. He cut and copied it into his computer so that the screen showed a fat waveform with jagged peaks where the louder parts were. Still the words were incomprehensible, but Gideon was undeterred, in his element. He twiddled knobs, applied filters and processed the audio so that the fuzz was reduced. Eventually, words emerged. The three of them listened in silence.

“Play it again,” said Harper, the blood draining from her face. Gideon pressed the space bar on his keyboard and the voice came through once more.

“Did you hear that?” said Amy, reaching for Harper. “Did you?”

“What did you hear?” said Harper to Gideon, needing to check, to make sure, that it wasn’t just because of what they thought they knew already.

“I’m not sure I know,” said Gideon. “Part of it sounded like, ‘Remember their names.’ ”

“What then?” said Harper. “What did the voice say the names were?”

“Well, it doesn’t make any sense.”

“Just say what you think you heard,” said Amy. “Please.”

Gideon said, “Did it say, ‘Their names are Bishop and Selver’? Like, the rivers?”

Harper tried to swallow the lump that had risen in her throat. “Yes, that’s what I heard too.”

Those unlikely names that Victoria had told them at the nursing home: Bishop and Selver, the two rivers that fed the New Riverby reservoir, the man-made lake that rose up a hundred years ago to drown the village of Selverton. The River Bishop that ran along the length of the valley, passing through the park, by the place the twins were taken. And the Selver that swirled into the reservoir, its new mouth since the walls went up, never again emerging to reach the sea.

In Harper’s head, Lauren spoke quietly. She’s from the water, that woman. Where the two rivers meet.

“What does it mean?” said Gideon.

“I don’t know yet,” said Harper, her voice reduced to a whisper.

“You have to go back to see Victoria,” said Amy.

Chapter 35

CHAPTER THIRTY-FIVE

On the journey across the city, Harper had too much time to think about why Amy had declined to come with her to talk to Victoria again. The two of them had walked back to the car together, Harper assuming they would both be heading to the nursing home. But when they’d got in and shut the doors, Amy asked to be dropped off at the Mail offices.