David's Gran has a mysterious liking for the famous painting 'The Scream'.

She has strange powers, and sends bad luck to people she doesn't like.

On her Scottish island home she was a 'Ridder' who could make troublesome rats run into the sea.

Now she has moved to the city to look after her orphaned grandchildren, but her dark secrets have come with her...A tense, exciting and disturbing new story from Joan Aiken, whose magical, fantastic and supernatural books for children are among the best ever written.