Parisian police commissioner Coleman (Alain Delon) is not a happy man, but he does what he can to get through each day. He has recently started having an affair with Cathy (Catherine Deneuve), and that helps a little. Cathy is also Simon's girlfriend and Simon (Richard Crenna) is Coleman's friend. Unfortunately, Simon is also the head of a gang of criminals. When Coleman's investigation of a drug-smuggling ring closes in, their rivalry comes to a head. One of the highlights of this film is a stunt involving a helicopter and a moving train.