The twins are in bed when it happens. They hear a sound like a wet cabbage hitting the wall. Then a clattering on roof tiles. Followed by a tapping at the window. It's a girl. With a broken wing. And she's here to stay.

Who is she? Where did she come from? And, more important, what does she want? The twins have no idea. Perhaps she's their guardian angel. But would an angel have filthy feet? Would an angel...snore?

The twins were in bed when it happened. They heard a sound like a wet cabbage hitting a wall, then a clattering on roof tiles – then nothing but the wind wuthering around the eaves once more.

“What was that?” whispered James.

Amanda, who slept behind a curtain on the other side of the attic, switched on her bedside light, and they lay very still, listening.

Rap, rap! Came a knock on the skylight.

“Who’s there?” said James. He climbed out of bed and stood under the window, and there he saw a startled face framed by a tangle of windblown hair. “It’s a girl!” he cried.