Marcus taps his own cheek. Two pink lines interrupt the stubble there: the scratches Will had noticed last week, now healing. "You were worried about these," he says, not because he thinks Will needs the reminder but because he's easing himself into the story.

"The woman who gave them to me, her name is Sister Clara. She told me I could tell you this. Told me she'd talk to you if you wanted to, but between you and me — that's because she's a generous soul. If you need to grill her, fine. But you do it gently, and you come to the convent for it, cos like hell am I gonna see her fretting in a police station." Marcus leans back, settles one of his ankles at his knee. "She wasn't sick. She was possessed. I wasn't ministering." He clicks his tongue, loud in the muted silence of the room and raises his hands, spread wide. Somewhere between surrender and ta-da. "I was exorcising."