“Yes,” Lizzie said, “much.” She took a deep breath. “OK. I’m just going to go for it. You mentioned in passing that Johnny has a bit of a habit of disappearing. Dudley said the same thing. I wondered whether you meant he would just wander off somewhere to be on his own and then come back when he felt like it, or whether there was more to it than that.” She saw Arthur’s frown and hurried on. “I mean, has he vanished for long periods of time before? Or has he—I don’t know—just seemed to be there one moment and be gone the next?” She thought she was probably expressing herself very badly but couldn’t see how to put it any better. She wasn’t ready to blurt out that she thought Johnny travelled in time and she didn’t think Arthur would be ready to hear that either.

Arthur started to speak then checked himself. “Why do you ask?” he said quietly.

Lizzie looked him in the eye. “I can’t tell you that right now. Please, Arthur, believe me, this is very important.”

“All right,” Arthur said. “But tell me first what Dudley said.”

“Not much,” Lizzie said. “It was whilst he was telling me about how he’d reported Johnny for threatening him. I’m afraid I jumped down his throat. I wish I hadn’t now, but at the time I didn’t realise how important it might be.” She closed her eyes for a second, trying to remember Dudley’s precise words. “He said that Johnny was always saying weird stuff and appearing and disappearing like a ghost and that once, at Oakhangar, Johnny and Amelia were playing some childish trick where he vanished like it was magic.”

Arthur had turned very pale and his mouth was set in a grim line. “It’s odd you should mention that,” he said slowly, “because my immediate reaction to what you asked was that yes, Johnny would sometimes wander off on his own but there was no more to it than that. Then I remembered something.”

Lizzie’s heart sped up. She found that she desperately wanted to eat another cupcake, as was so often the case when she felt stressed, but this wasn’t the moment to order a third so she sat on her hands.

“It was when Johnny was a kid,” Arthur said, “about seven or eight, I suppose. We were at our dad’s place in Norfolk, and Johnny just disappeared, literally seemed to vanish into thin air. He was gone for hours. Jess, Johnny’s mum, was frantic. We searched everywhere and then he just popped up again as though nothing had happened. He said he’d been playing with Amy. We assumed he meant Amelia and that made Jess even angrier because Amelia wasn’t even there that day so he had to be lying.”

Lizzie’s mouth was dry. “Perhaps he wasn’t lying,” she said. “After all, that’s pretty much what he’s done now.”

There was a very long silence. She let it spin out.

“Jules told me about the CCTV,” Arthur said at last. “I haven’t seen it but I have to admit that was what it sounded like.” He met her gaze. “You do know what you’re suggesting?” He sounded almost angry. “You’re implying that Johnny has the ability to travel to a different dimension of time, which is a physical impossibility.”