A nationwide hunt is on for Katy and Josh, missing from a children's home. But who would connect their disappearance with a trip to Alton Towers the previous week? A trip which gave both children the need for the warmth and comfort of real family life.

But though Katy and Josh dream of the fun they'll have living at Alton Towers, they soon discover that when darkness comes and the crowds have gone the place becomes eerie, with dark shadows and the sounds of the night. There, in that other world, Katy and Josh meet goodness and evil, and discover the terrifying mystery of Alton Towers...