“Besides,” said Ava, “how do you think I’d cope without you? There is literally no-one else on the entire planet who would think to buy me a Winston Churchill biscuit tin.”

“Actually, I nicked it. I waited until the woman went for a cup of tea and then I walked out with it.”

“But it’s huge! How did you get away with it?”

“I pretended to put some money in the pot and I walked out with it under my arm. No-one said anything. Well, Marie asked why I wanted it, but I said I’d keep pencils in it, and she was happy with that.”

“A criminal mastermind. I should probably tell you off.”

“If anyone asks, I’ll tell them you were really severe.”

“It’s a deal.”

“Together we’re invincible,” Finn said.

Ava nodded. “Us two against the world.”

The sleeping dog

The wild wood was the secret home of many strange people. There was an elderly couple with tangled grey hair who lived in a cave and never wore clothes. They spent their days digging tunnels deep, deep underground, and then they filled the tunnels with secret bonfires to warm the soil, so they could welcome the Winter Solstice with armfuls of daffodils. There was a tall bony woman with the head of a parrot, who kept sparrows in silver cages. The sparrows had miniature men’s heads and sang operatic arias in deep, mournful voices. There was a huge white tiger, said to have the power of speech (although apparently it had never yet met anyone interesting enough to talk to).

And in the wood’s tangled heart was a clearing, and in the clearing was a house built from smooth white pebbles and a thick coat of whitewash. It was the cleanest, emptiest house in the whole world – so clean and empty you’d almost think it was deserted.

Almost, but not entirely, because you’re far too clever to actually think that. If you ever came across this house, you’d quickly deduce that:

A house with no people never stays deserted for long. Before sunset on the first day, a thousand creatures creep in and make their own dusty, grassy, webby, leafy homes in there, turning the house into a busy miniature city. And therefore:

The house must have at least one person living in it, sweeping the house free of all the life that creeps through the window-frames and scuttles down the chimney and blows in through the open doorway.

And, of course, you’d be right.

The man who owned the house lived alone, and nobody knew his name or anything about him, although he was perfectly polite and always well-mannered. He wore white clothes, ate only vegetables and grains, and had almost no possessions. There were no books in the corners and no pictures on the walls. His bed was a washed white flour-sack stuffed with pale dry straw and covered with a soft cream woollen blanket. He had a chair made from bleached wood and clean bones, and a table of cool unmarked marble. He kept his cooking-fire shut up in an iron stove so it couldn’t escape and cause trouble, and every Sunday he scrubbed the walls down to the bare stone and applied a new coat of whitewash.