Charles Thnier's nine year old son is run over by a reckless driver. He vows to have his revenge, yet the police investigation is fruitless. Partly following his hunches and partly by chance he discovers actress Hlne Lanson is the owner of the car. He seduces her under a false name as part of his revenge plan, but loses courage to carry it through as he develops feelings for her.
He finds out shortly after that the real killer is her brother-in-law Paul Decourt, a man detestable even to his own family. While Charles is left with conflicting thoughts as to whether or not kill him, Paul's teenage son, Phillipe, confides in him his own wishes to see his father dead.