Dr. Jeremy Lodge (Jamie Gillis), a very strict father and psychologist, has sent his two daughters to boarding school. The eldest daughter, Naomi (Karen Summer) is caught having sex in her dorm and is kicked out of school. When the two sisters return home, Dr. Lodge discovers that his wife (Cyndee Summers) has had an affair with his brother (John Leslie) and angrily throws her out. Naomi chooses to live with her mother and uncle (later revealed to be her biological father), while Robin (Ginger Lynn) chooses to stay with her father. Naomi (the "bad girl") seduces her uncle and has sex with him, while Robin (the "good girl") develops a yearning for her father. Dr. Lodge runs an incest support group and his patients include Joyce McBride (Honey Wilder) and Barbara Scott (Kay Parker), who only appears in the film in brief flashbacks.
Diana is a Roman wife happily married to sympathetic Paolo but she is keen on playing benign games of seduction with other men while resisting the advances of chic lingerie shop owner Silvio and she narrates her adventures to Paolo in order to stimulate their otherwise monotonous sexual life.
Joan Wilder is thrust back into a world of murder, chases, foreign intrigue... and love. This time out she's duped by a duplicitous Arab dignitary who brings her to the Middle East, ostensibly to write a book about his life.
Billy Wong is a New York City cop whose partner is gunned down during a robbery. Billy and his new partner, Danny Garoni, are working security at a fashion show when a wealthy man's daughter, Laura Shapiro, is kidnapped.