Rainy Day Women by Jane Yardley
It is 1971 - hippies, hot pants and extraordinary footwear. Jo is fifteen, and there is something very wrong at home. The house, an architectural oddity built by an eighteenth-century madman, always had a life of its own but now its sinister goings-on are getting worse. The capable Jo has always coped with her eccentric family but they're getting worse too - and where are her parents? As the Red House crumbles around them, she and her best friend Frankie are determined to solve the mystery so Jo's family can start an ordinary life. But along comes the devastatingly attractive Florian, folk singer and opportunist, to cause a chaos all his own...