On holiday with their mother in the Lake District in 1929 four children are allowed to sail over to the nearby island in their boat Swallow and set up camp for a few days. They soon realise this has been the territory of two other girls who sail the Amazon, and the scene is set for serious rivalry.

In Roman Polanski’s first English-language film, beautiful young manicurist Carole suffers from androphobia (the pathological fear of interaction with men). When her sister and roommate, Helen, leaves their London flat to go on an Italian holiday with her married boyfriend, Carole withdraws into her apartment. She begins to experience frightful hallucinations, her fear gradually mutating into madness.