Cathy is 14 years old. She is fat and unattractive, but has a bright gleam in her eye. She has a wild imagination, almost too wild. She dreams up all kinds of imaginary characters: an orbiting satellite that helps her with her homework, and a certain Catherine, a gorgeous woman straight out of a glossy magazine, who owns a chain of trendy fitness clubs. Then there is Sister Welsh, who lives in 19th century Plymouth, England. Sister Welsh is a romantic, in love with Captain Grant, a man sailing the high seas. All these characters are interwoven in Cathy's head, where reality and fantasy become one.