In San Francisco, homicide detective Nick Curran investigates the murder of retired rock star Johnny Boz, who has been brutally stabbed to death with an ice pick during sex by a mysterious blonde woman. Nick's only suspect is Boz's bisexual girlfriend, crime novelist Catherine Tramell, who has written a novel that mirrors the crime. It is concluded that either Catherine is the murderer or someone is attempting to frame her. Catherine is uncooperative and taunting during the investigation, smoking and indecent exposure during her interrogation. She has an alibi and passes a lie detector test. Nick discovers Catherine has a history of befriending murderers, including her girlfriend Roxy, who killed her two younger brothers, on impulse, when she was 16, and Hazel Dobkins, who killed her family.
Catherine Tramell becomes the suspect when her boyfriend is found murdered. Psychoanalyst Michael Glass examines her, but with every session, he is entranced by her seductive and manipulative nature.