Cécile (Virginie Ledoyen), a young woman from a working-class background, and her friend attempt a botched mugging of a wealthy, middle-aged lawyer, Michel Farnese (Gérard Lanvin). Caught in the act, Cécile goes to Michel's office to persuade him not to press charges. Captivated by her youth and beauty, Michel decides to defend her in court for free. Despite being married to his elegant wife Viviane (Carole Bouquet), Michel becomes dangerously obsessed with Cécile and begins an affair with her, while Cécile remains torn between Michel's wealthy lifestyle and her petty-thief boyfriend Antoine (Guillaume Canet).