This Man Must Die

This Man Must Die, also titled Killer! in the UK, is a 1969 French–Italian psychological thriller film directed by Claude Chabrol. It is based on the 1938 novel The Beast Must Die by Cecil Day-Lewis, writing as Nicholas Blake. The story follows a widower who, obsessed with revenge after his only son is killed in a hit-and-run incident, tracks down the driver with the intent to kill him. Plot Returning from the beach, Charles Thénier's young son Michel is fatally hit by a sports car, whose driver escapes without stopping. Charles vows to have his revenge, keeping a journal in which he announces to kill the offender once he finds him. The police investigation is fruitless. Charles thinks the guilty party may run a garage, since there is no record of a car going in for repairs. By chance, while pursuing this hunch, he discovers that the actress Hélène Lanson was the passenger in a car that was damaged on the day of his son's death. Adopting a pseudonym, he seduces her and discovers that the driver was her brother-in-law Paul Decourt. Hélène confesses that she once slept with Paul so Charles presses her to explain more of her anxiety about Paul but she refuses to add anything. He arranges a trip with Hélène to visit her sister's family in Brittany. Charles discovers that Paul is detestable, cruel to his wife and hated by his teenage son Philippe. He has conflicting thoughts as to whether or not he will kill Paul but, although hesitatingly, rescues him from a cliff-fall. Philippe confides to Charles his own desire to kill his father.