In Marseille, a serial killer raped women in some rich villas and beat the victims to death. Detective Louis Schneider was ordered to investigate. Schneider was exhausted because his daughter died in a car accident a few years ago and his wife was disabled for life. He became an alcoholic. The young woman Justine had difficulty overcoming the nightmare of the past because she saw her parents being brutally murdered 25 years ago, and she learned that the murderer was about to be released. She got together with Schneider because of the murderer's release. The director of this film, Olivier Marchal, was a policeman. He launched "36 Quaide Sorfeld" (the site of the Judicial Police Bureau) in 2004. "MR73 Revolver" was adapted from a real case he participated in investigating in 1981. The title refers to the "Monster Python" 357 revolver produced by the Manurhin factory in 1973. This weapon is used by the elite French gendarmerie.