Marseille. 1975. A young magistrate with a wife and children, is transferred to help in the crack-down on organized crime. He takes on French Connection, an operation that exports heroin the world over. Paying heed to no one's warnings, he leads a one-man campaign against kingpin Gaëtan Zampa, the most untouchable godfather of them all. But soon he understands that to get results, he will have to change his methods.