In the psychiatric ward of a prison, Alan Musgrave, who calls himself "Mollymauk" after an extinct duck-like bird, tells his story into a tape recorder. Alan and Barbara Ann Greene are both senior transfer students at Los Angeles' new, ultra-modern Consolidated High School. Under Alan's hypnotic spell, Barbara Ann reveals her desire to be popular. Alan assures her that he will make her every wish come true. First, Barbara Ann wishes to join a sorority whose members must each own a designated number of cashmere sweaters, and Alan has her persuade her father to buy sweaters. To keep Barbara Ann from failing any courses, Alan has her use her sex appeal to obtain the job of secretary to the principal. Barbara Ann then meets wealthy and handsome college senior Bob Barnard during a sex seminar at a drive-in church, and she decides to vacation at Balboa, where Bob is to be chaperon. Alan takes her to Balboa, where he sets up a possible screen test for Barbara Ann with a producer of beach-party movies. Bob, who is in love with Barbara Ann, has problems with his zany mother, so Alan installs himself in the Barnard house and takes over the management of Mrs. Barnard by introducing her to alcohol. Mrs. Barnard discovers that Marie, Barbara Ann's divorced mother, is a bar girl and tries to end the romance. Thinking that she has ruined her daughter's life and her own, Marie commits suicide. Later Bob and Barbara Ann marry, despite Mrs. Barnard's objections. Bob, who has graduated and become a marriage counselor, disapproves of his wife's career in movies, and Alan decides to eliminate him. Bob proves almost indestructible, but by graduation time Alan has put him in a wheelchair. At Consolidated's graduation, he pursues Bob with a bulldozer, eliminating him and everyone on the speaker's platform as well. Barbara Ann goes on to Hollywood fame as the star of "Bikini Widow". In the prison, Alan tries to explain why he did it all, confessing that it might have been for love.