James Byrne had changed four thousand locks and had been in perhaps nine hundred houses where something bad had happened, and had never once believed in any of it.
He sat up.
The room was empty. The room was very obviously empty; there was a mattress, eleven boxes, a sofa with its back to the window and a man of thirty-four sitting bolt upright in the dark with his heart going like a hammer.
"Right," he said, out loud. "No."
"It blocks the light," said the voice. "That's the only good thing in here and you've put a sofa in front of it."
He did not sleep.
He sat on the sofa — which was, now he looked at it, in the wrong place — with every light on, until half past four, and at some point around three the voice said, in a completely different tone:
"You can hear me."
"No."
"You answered me."
"I did not answer you."
"You said no," said the voice, "which is an answer, and I have been in this building for nine weeks and you are the first person who has said anything to me at all."
Here is what James Byrne did, over the following four days, in order.
He checked the flat for speakers, which took two hours and was extremely thorough, because he is a locksmith and knows what a device looks like.
He rang his brother and said nothing about it.
He went to the doctor and described, in careful and dishonest terms, some difficulty sleeping, and came away with a leaflet.
He drank on the Wednesday, quite a lot, specifically to find out whether it got worse or better, and it got neither, which frightened him more than either would have.
And on the Thursday night he sat down on the floor with his back against the radiator, and put his hands over his face, and said:
"All right. Who are you."
"Sylvie," said the voice. "Sylvie Marsh. I lived in flat two."
"And what happened to you?"
There was a pause of the kind that would have been, in a living person, somebody deciding how much to say.
"That," said Sylvie Marsh, "is the entire problem."