Returning from the beach, Charles Thénier's young son Michel is killed by a hit-and-run driver in a sports car.

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.

However, while at sea, Paul pulls a gun on him and reveals that he has read Charles's journal and passed it to his solicitor to take to the police should something happen to him.

In a roadside restaurant, a television announcer reports Paul's death from poisoning and appeals for Charles and Hélène to return, which they do.

She wakes to find his note explaining that Philippe has confessed to the crime in order to save him and he (Charles) is the real murderer.

While calling it "surely one of the best new movies" which "adds wonderful moment to wonderful moment" and features "an idiomatic performance" by Jean Yanne, Greenspun also notes a shedding of "ironic strangeness" and a move towards the direct and sentimental in Chabrol's methods, and an ending whose images fall behind the director's usual technical capabilities.

[2] Roger Ebert gives the film 4 out of 4 stars, calling it "a macabre, bizarre study of the hazards of revenge, and it thrills us not with chases or cliff-hangers.... but with the relationship between good and evil people....