He didn’t reply but continued racing round the room, ripping up the paper, so I went over and grabbed hold of both his arms.

“Charlie,” I said. “Stop for a minute. Look at me. If you didn’t draw these, then who did?”

He stared down at the floor, his lower lip trembling slightly. Finally he looked up and said in a whisper, “Did you ever have a secret friend? One you weren’t allowed to tell anyone about?”

I frowned. “Well … I had an imaginary friend once. He was a giant rabbit called Podge. Is that the kind of thing you mean?”

But Charlie was already shaking his head. “No,” he said. “It’s not like that. It’s not like that at all.”

“Why don’t you tell me what it is like then?” I asked. “Look, you can trust me. I promise I’ll believe you, no matter how strange it sounds.”

Charlie paused and for a moment I thought he was going to confide in me. But then he shook his head and said, “Just kidding. I drew them really. It’s dangerous to go outside. The birds have gone mad. We’ve got to stay in the lighthouse. If we go out, the 230birds will tear us to bits and gobble up our insides.”

He held up a drawing for me to see, and I shuddered at the sight of birds eating someone’s guts. I assumed it was meant to be one of the guga hunters because they were wearing blue overalls. They were lying on the floor with their pink intestines trailing out on to the ground like eels, while the birds gathered round, crowded together as if they were at a buffet.

“Did you see the birds acting strangely when you were out with Dad and your mum today?” I asked.

But Charlie seemed to have finished talking. He wriggled free of my grip and went back to scooping up the drawings. As he did so, I saw there was faded writing on the back of them and realized that these were more letters.

“Charlie, where did you get these?” I asked, snatching a handful from the wall. When I flipped them over, they were all covered in the same neat handwriting I’d seen before.

“Don’t take those!” Charlie said. “They don’t belong to you!”

“Where did this paper come from?” I asked again.

Charlie paused, then spoke in almost a whisper. “My friend gave them to me. But I’m not supposed 231to talk about it.”

I tried to prise further details from him, but it was no use – he clammed up completely. Finally I left him to it and went upstairs to check the Strangers’ Room. After what had just happened, I wanted to be sure there were no more birds in there but, to my relief, the window was shut and the room was empty.