Paris, 1933. The daughter of a respectable lower middle class couple, Violette Noziรจre, leads a disreputable double life. Far from being the innocent 18-year-old her parents mistake her for, she spends her nights with dissolute young men in the less salubrious areas of the city. One day, Violette meets her ideal man, Jean Dabin, but he is a scoundrel who soon begins to extort money from her. When her parents discover that she is stealing from them, Violette finds the tension in their cramped apartment unbearable and she is driven to murder both her parents.
