 A former rockstar Johnny Boz is brutally killed during sex , and the case is assigned to the Detective Nick Curran of the SFPD . During the investigation , Nick meets Catherine Tramell , a crime novelist who was Boz s girlfriend when he died . Catherine proves to be a very clever and manipulative woman , and though Nick is more or less convinced that she murdered Boz , he is unable to find any evidence . Later , when Nilsen , Nick s rival in the police is killed , Nick suspects of Catherine s involvement in it . He then starts to play a dangerous lust-filled mind game with Catherine to nail her , but as their relationship progresses , the body count rises and contradicting evidences force Nick to start questioning his own suspicions about Catherine s guilt .