A small-time thief steals a car and impulsively murders a motorcycle policeman. Wanted by the authorities, he attempts to persuade a girl to run away to Italy with him.
Vallois, a vice inspector for the Paris police, takes special interest in the plight of drug-addicted Lucky (Najda Tiller), whom he considers to be more victim than criminal. Taking it upon himself to wean Lucky away from narcotics, Vallois also wins her love -- and, incidentally, smashes the dope ring responsible for her addiction.
Petrus, a Montmartre photographer, is accidentally wounded by Migo, a dancer at the Frou Frou night club, when she is trying to shoot her faithless lover Rodrigue, a counterfeiter. Though Petrus tries to reconcile the lovers, Migo lands up with him after Rodrigue is finally killed by another jealous dancer.
