Four murders in forty-eight hours happen in Nice. The murderer calls himself "The Exterminator" and the police are unable to catch him. Tom Lepski is an insurance detective and he get involved in the investigation when Liza Mendoza, a famous violinist and a friend, is killed just a few minutes before Tom visit her. After another rich woman killing, Tom finds out that all the victims were members of the exclusive Fifty Club. All of them but Lisa.
Good dope is becoming rare in the North of Paris. Drugstores are being raided by junkies and gangs are nervous, fighting each others: the 'Viets', the 'Blackies', the 'Arabs', the neo-nazis 'Justiciers' and some mean gays. Vincent (Daniel Auteuil) is the good cop coming from Marseilles where he was a gangster. He's a soft method guy but also kicks assses hard and throw lethal dialog lines when needed. With the precious help of 'l'Arbalète'* (Marisa Berenson**), a tox' prostitute ex-member of Vincent's former gang, he will try to put order in that mess. There's also a violent and racist cop (Marcel Bozzuffi), Algeria veteran with hard methods, whose role could be more than to protect and to serve.
Having developed a revolutionary device that puts water in the mouth of all secret services in the world, professor Forrester is about to go on a conference in San Francisco under the protection of Tom Lepski, an insurer.
Movie star Barbara Jenkins arrives in Cannes to host an auction of her costumes, under protection of Tom Lepski. She is under surveillance of a political terror group and some wily jewel thieves.
The story (based on a novel by James Hadley Chase) concerns the efforts of the genial and deceptively tentative Lepski (Michael Brandon), an insurance company detective, to track down a valuable medieval Russian icon, which was stolen by Bradley (David Carradine), a master thief.
