"I bet there are rats around the back," I said.

"I bet there aren’t."

"You go first."

"Okay." She started down an alley between one warehouse and the next. There was lots of broken glass lying around and grass growing up through the pavement.

"I bet there are snakes," I said, following her.

"Shut up, Jamie."

The back was only a strip of weeds two yards wide, stuck between the warehouse and a chain-link fence. Halfway along was a flight of metal steps, like a fire escape leading to the roof. They creaked when you walked on them, but didn’t wobble too badly.

On the roof we found a weird-looking airplane. Or boat. Or train. Or wagon. Whatever it was, it had wings and a tail like an airplane, but its body was built like a boat: a bit like our motor-boat up at the cottage, but bigger and with these super-fat padded chairs like maybe astronauts sit in. The whole thing was attached to a cart, but the cart’s wheels were on the near end of a train track that ran the length of the roof and off the front into the street.

"What is this thing?" I asked.

"The monks made it for me," Muffin said, which didn’t answer my question. She climbed up a ladder into the plane and rummaged about in a cupboard on the rear wall. I followed her and watched her sorting through the stuff inside. "Peanut butter. Bread. Kool-Aid. Water. Cheese. Diet Coke. What’s this?" she said, handing me back a roll of something in gold plastic wrapping.

I opened one end and sniffed. "Liverwurst," I said.

She made a face. "Is that like liver?"

"No, it’s peanut butter made from bologna."

"Weird. Do you see any hot dogs?"

I looked in the cupboard. "Nope."

"I should phone the monks. We need hot dogs."

"What for?"

She ignored me. "Is there anything else you’d want if you were going to be away from home for a few days?"