Rose runs to catch up with me. “Arthur, do you honestly think we can go back to Grandad’s attic, play around for a bit, and a boat will turn up here in Roar?”

“Why not? It used to work, didn’t it?”

“Yeah, when we were five or six!”

“It’s got to be worth a try,” I insist. “Otherwise we just have to wait for Crowky to turn up with the Box. This way we might be able to find it before he does!”

“Without the picture of the tattoo?” she asks, one eyebrow raised.

“Maybe,” I say. “You know Mitch better than anyone. Perhaps you can work out where she’d have hidden it. Please, Rose. We’ve got to do something!”

Win wriggles between us. “What do you mean you’re going to play boats and make one appear?”

I spoke without thinking: Win doesn’t know that Rose and I made everything in Roar, including him. So I say the first thing that comes into my head. “It’s what our magic is called: playing . . . It’s rare . . . It takes ages to learn.”

Win gasps. “I did not know that you two could do magic! You should have told me. How does playing work? Wands? Spells? Potions? Oh . . . do you use unicorn hair?”

Rose and I share a look. I think we both know that the truth would be too much for Win to handle. Everything in Roar began as a game, including Win. He appeared after Grandad went to a garage sale and came back with a too-tight ninja costume that I put on and refused to take off.

“Playing mainly uses words,” says Rose carefully.

“Show me!”

“We can’t,” I say. “It only works in our grandad’s attic.”

“So if you say some words in your grandad’s attic, you can magic up a boat in Roar?” Win sounds skeptical.

“Sometimes we use enchanted stuff,” I say, thinking of the toys and dressing-up clothes we used to love playing with.

“Imaginary . . . ,” whispers Win. “Can I come and watch?”

“No!” says Rose quickly. “Playing needs total concentration. Right, Arthur?”

I nod. “Anyway, we need you to sit on the ledge with the telescope and tell us when the boat appears.”

Win is obviously disappointed. “OK, but if your magic works and the boat turns up, am I allowed to crawl through the tunnel to Home and tell you?”

“Yes,” says Rose. “Just this once.”

He beams. “Then I’ll need something that belongs to you.”

In the end Rose gives Win a sneaker. He cradles it in his hands as if it’s a priceless jewel and promises to guard it with his life. Then he leads us up the side of the waterfall, jumping easily from rock to rock. We leave him at the entrance to the tunnel.