Laura was still looking awkward. Walden felt she had to say a bit more. “Yes, all right, I was there. We were seventeen years old,” she explained, “and very talented. Worse, we knew we were very talented. Charlie was a School House boy, a sorcerer—you know what that means, of course you do, you’ve worked here long enough. I didn’t actually know very much about his background, I realise now. I’m sure he didn’t want to tell me. But you don’t end up as a ward of Chetwood School without a ferocious talent for magic. He was good. So was I. When I look back, I still don’t know if it was his idea or mine. There’s no excuse. We weren’t tricked into it like poor Nikki was tonight. We just wanted to see if we were good enough to summon and control an absolutely enormous demon. And, of course, we weren’t.” She drank some more tea. “It was May half term, right before our A-levels. Charlie had an Oxford offer—an EE offer, if you can believe that; he must have really impressed the interviewer. So did I, but my offer was three As. Which I knew I would make. We felt like lords of the world, magician-kings to be, masters of the arcane disciplines … you know. Children. Old enough to know better, but we didn’t, yet.”

Laura had set her tea down and was watching her gravely. Come to think of it, it was a long time since Walden had told anyone this story.

“The school was mostly empty,” she went on, “though there are always a few still here over the holidays. My parents were in Barbados. Charlie … well, as I said, he was a School House boy. We had just enough sense not to try it in a dormitory. We snuck out to the old cricket pavilion. Hence the new cricket pavilion, because in the course of trying to fight our way out, we demolished it. We failed, of course. Really, we should both have died, but the school Marshals took the very risky decision to send a team in after us. Looking back, it was very brave of them. At the time…” She shook her head. “It was already too late for Charlie. They dragged me away. I heard him screaming. And then they collapsed the incursion.”

“No wonder you don’t like Marshals,” said Laura.

Walden rolled her eyes. “Give me some credit for being an adult, Laura, it was twenty years ago. I don’t like Marshals in school because, frankly, I don’t think intimidation is the best way to persuade children to think about the consequences of their actions. It certainly didn’t work on us. Does that answer your questions?”

Laura said, “So he was your…”