While celebrating his birthday, police inspector Basquier recalls two of his most celebrated cases. The first involves duplicitous moneylender Olga. The second concerns the brutal broad daylight murder of innocent young Yvonne.

Madame Rose runs a seedy hotel in a suburb of Paris. Strong-minded but without the least moral scruple, she once killed her husband whose honesty was a hindrance to her business. Under a suspended sentence, she now indulges in smuggling. One day, Victor, one of her former accomplices hounded by the police, finds sanctuary with her. During a drinking spree, he has the bad idea to entrust to her a suitcase filled with bank notes, a loot with which Victor hopes to rebuild his life in South America. But Rose, lured by temptation, betrays Victor, who is arrested by the police. However, he manages to escape with only one thing in mind, to take revenge on Rose...