The rhythmic scrape of a pencil—at that stage I could hear the tiniest sound coming from inside that flat, I could probably have heard the two of them blinking. Holly said, “What about Uncle Kevin?”

There was another fraction of a pause before Shay said, “What about him?”

“Did somebody kill him?”

Shay said, “Kevin,” and his voice was twisted into an extraordinary knot of things that I had never heard anywhere before. “No. No one killed Kevin.”

“For definite?”

“What’s your da say?”

That shrug again. “I told you. I didn’t ask him. He doesn’t like talking about Uncle Kevin. So I wanted to ask you.”

“Kevin. God.” Shay laughed, a harsh lost sound. “Maybe you’re old enough to understand this, I don’t know. Otherwise you’ll have to remember it till you are. Kevin was a child. He never grew up. Thirty-seven years old and he still figured everything in the world was going to go the way he thought it should; it never hit him that the world might work its own way, whether that suited him or not. So he went wandering around a derelict house in the dark, because he took it for granted he’d be grand, and instead he went out a window. End of story.”

I felt the wood of the banister crack and twist under my grip. The finality in his voice told me that was going to be his story for the rest of his life. Maybe he even believed it, although I doubted that. Maybe, left to his own devices, he would have believed it someday.

“What’s derelict?”

“Ruined. Falling to bits. Dangerous.”

Holly thought that over. She said, “He still shouldn’t have died.”

“No,” Shay said, but the heat had gone out of his voice; all of a sudden he just sounded exhausted. “He shouldn’t have. No one wanted him to.”

“But someone wanted Rosie to. Right?”

“Not even her. Sometimes things just happen.”

Holly said defiantly, “If my dad had married her, he wouldn’t have married my mum, and I wouldn’t have existed. I’m glad she died.”

The timer button on the hall light popped out with a noise like a shot—I didn’t even remember hitting it on my way up—and left me standing in empty blackness with my heart going ninety. In that moment, I realized that I had never told Holly who Rosie’s note had been addressed to. She had seen that note herself.

About a second later, I realized why, after all that adorable heartstringtugging stuff about hanging out with her cousins, she had brought along her maths homework today. She had needed a way to get Shay alone.

Holly had planned every step of this. She had walked into this house, gone straight to her birthright of steel-trap secrets and cunning lethal devices, laid her hand on it and claimed it for her own.