The twins are in bed when it happens. They hear a sound like a wet cabbage hitting the wall. Then a clattering on the roof tiles. Followed by a tapping at the window. It’s a girl called Hilary....

When Ibby is sent to stay with her aunt, she discovers her troublesome boy cousins, Francis and Alex, playing with an old box of magic tricks they found in the attic.

Ibby is sure that...