“For Christ’s sake.” His face twists in disgust. “It’s a fucking house! It cannae feel! It cannae speak!”

“Oh, but it can,” I say, suddenly catching on to Fiona’s plan. She gives a small nod. “It’s been speaking, but I haven’t been listening carefully enough. It’s been trying to tell me that you’ve been coming in through the bathroom window. It’s been trying to tell me that you stole the picture of your mum from the album in the attic.” The light flickers again as thuds come from upstairs. There must be three or four doors slamming now. The shotgun is still trained at my stomach. His hand is still clamped round my upper arm, so tightly that I will have bruise marks. If I’m alive to have them.

“The bathroom window?” asks Carrie faintly.

“There must be a ladder hidden somewhere. He’s hardly Spider-Man. I’m guessing he used to have a key, from when he worked at the estate agent’s, but then I rather unhelpfully got the locks changed. He’s been coming in with my father’s bones. He likes to lay them out and have a cigarette. Sometimes he’s not so careful about collecting up all the little bits.”

Jamie’s jaw clenches at the revulsion that crosses Carrie’s face. “Our father’s bones, mind.” A gust of wind strong enough to rattle the kitchen windowpanes blows for a few seconds, accompanied by flickers of the light overhead and a string of thuds and bangs.

“How would our father feel about you pointing a shotgun at me?” It’s a misstep. For the briefest of moments, I see how much he wants me to believe in a fantasy future of the three of us living here, Norman Bates style. But I’m not the actress Carrie is. And he’s not stupid. “Stop trying to play me, you cunt,” he says brutally. “Dinnae think I willnae end you just cos you’re my sister. I will. I’m gonna.”

Carrie’s gray eyes leap to mine. I can see her horror and there is nothing I can do. I’m all too aware of the metallic barrel at my stomach. I’m helpless. I’m sorry, I say soundlessly. The kitchen door starts to swing farther ajar with a loud creak behind Jamie. He glances round quickly, then lifts his foot and boots it firmly closed behind him, like a horse kicking out.

“Sister,” says Fiona suddenly. “Based on what?”

“I told you,” says Jamie impatiently. “DNA testing.”

“You gave him a sample?” Fiona asks me, frowning.

I shake my head, but very carefully, given the proximity of the shotgun. “He took one anyway.”

“Hairbrush,” Jamie says, almost gloating. Too easy, I can see him thinking. “From your bathroom,” he says to me.

“What color?” Fiona asks. There’s something about her manner, a sudden excitement. It catches Carrie’s attention too.