Steve Ventura, head of the American Narcotics Bureau in Paris, is frustrated in his efforts to establish any evidence against crime czar Jacques Brizard, who operates a drug-smuggling syndicate out of Marseille. When one of Ventura's agents, Matthews, is killed, Ventura's anger and guilt prompts him to secure the unofficial help of French Inspector Briac in hiring a professional assassin to dispose of Brizzard.