“Oh, this is the real one. I got the other one on eBay. I bet you hadnae a clue you can buy human remains right off the Internet. Some people are fair sick in the head.” He shakes his own head. “The finger bones Callum found were his, though. I cannae think how I missed them.” He frowns, evidently annoyed at that slip. “This is his favorite place to be, you ken. I like to bring him here as much as I can.”

“How do you know . . . that it’s him?” My mouth is too dry; it’s difficult to speak. The teeth, a whiter shade of ivory than the bone in which they’re set, humanize the skull in a way that makes it even more disturbing.

He laughs. “I always kent it. I found him first, you see. I ran away, and that’s when I found him. It was fate. Glen was furious at me for running away; he fair lost it when I came back. More than tanned my arse, Fi will tell you that. Child abuse, it was.” His jaw is tight. “No wonder I ran away. But the point is, I found him first, as I was meant to, and I found his wallet. Credit cards dinnae biodegrade.” He smiles a slow, secretive smile with the half of his mouth that’s nearest the lamp; the rest of his face is in shadow. “D’you ken what else I found?”

I do. I’m already ahead of him. “The diamonds.” I doubt he’s ever traded a day in his life. I should have made the connection already; he had none of the paraphernalia—extra screens, Bloomberg keyboards and the like—that I saw at the desks of the financial geeks in the newsroom.

“Top of the class!” he crows. “You’re a smart one, Ailsa. Runs in the family, I guess. I didnae ken what they were or what they were worth until I got older. And it took a fair while after that to figure out where to go to trade them. If I’m honest, I spent too much at the beginning. And the way house prices have been rocketing . . . But I’ve kept enough to buy this place if it doesnae get bid up. And let’s face it, who else would want it with all the stuff that goes on here?” He suddenly grins again. “I should really thank Morag; she gave me the idea.”

“What idea?”

“To scare you so you’d sell at any price. But now I dinnae need to buy it after all. You and I will share it.”