The drug investigator Mangin is someone who likes to play by his own rules, but has considerable successes in the fight against crime. During his investigations, the professional, whose marriage has failed due to his job, meets the girlfriend of a dealer he has arrested. While her lover is behind bars, she has taken drugs and two million francs and now sees herself hounded by the prisoner's brothers. The girl gradually becomes a key figure in a life-threatening game in which she deceives all parties with permanent lies and contradictions. But Mangin develops real feelings for someone again for the first time and finds himself in a hopeless situation.