Eleven-year-old Sandy Henderson lives a carefree life with her family in a quiet port on Scotland''s south-west coast, unaware that the parallel world of Sylvania lies beyond a huge hedge at the bottom of their overgrown garden. When her beloved cat, Leo, tumbles headlong into this enchanted land, while they're exploring unfamiliar territory, Sandy undertakes a dangerous journey to bring him home again. In the company of Jock, a handsome, swaggering crow, and the Hendersons' haughty Siamese cat, Jamie, Sandy encounters a host of colourful characters along the way, all of whom have the power of speech, including Pongo, the hairiest dog imaginable, master of quips and 'one-liners', Lorimer, an outrageous lobster who lives by the motto 'Dress to Thrill!', and self-serving 'Captain' Pestilence Grimshaw who joins forces with Maligna the Harpie, the monstrous entity whose sole preoccupation is the destruction of everything Sylvanians hold dear. Sandy quickly discovers that Scottish fairy folk are witty, resourceful and tenacious, even when faced with evil on an unprecedented scale. Will she be in time to save Leo? And will Sandy and her companions ever see Scotland again?