Twelve-year-old Anaïs is fat. Her sister, fifteen-year-old Elena, is a beauty. While the girls are on vacation with their parents, Anaïs tags along as Elena explores the dreary seaside town. Elena meets Fernando, an Italian law student; he seduces her with promises of love, and the ever watchful Anaïs bears witness to the corruption of her sister's innocence. Fat Girl is not only a portrayal of female adolescent sexuality and the complicated bond between siblings but also a shocking assertion by the always controversial Catherine Breillat that violent oppression exists at the core of male-female relations.