A newly married attorney accepts the murder case that could establish him as a top defense lawyer, only to find himself hopelessly intertwined with a prime suspect after meeting the mysterious beauty at the scene of the crime. Approached by this brother with a case that seemed especially difficult, ambitious lawyer Lucien Lambert agrees to defend a woman accused of murdering her husband in cold blood. Blanche Kaplan is going to trial for murder. Despite the fact that Blanche has an airtight alibi, the case against her is strong due to the fact that her fingerprints were all over the knife that was used to kill her husband. As Lucien begins to investigate the case by exploring Blanche's home, he happens across a strange but mesmerizing woman named Marguerite who seems to have taken over the abandoned abode. In the days that follow, Lucien and Marguerite enter into a bizarre game of seduction and persecution - often interacting like a married couple as they dine together, discuss the events of their day, and grow increasingly intimate. Later, as Marguerite admits to Lucien that she had been having an affair with Paul Kaplan, plain close policeman Louis Berger observes their actions from afar. Yet despite the fact that her recent confession has made Marguerite a prime suspect, Lucien's view of her has become hopelessly biased since he has fallen completely in love with her. Now that Lucien has become blinded by his feelings for Marguerite, it's up to detective Berger to uncover the truth and capture the killer.