A simple man gets involved in an implausible story of gangsters in the wake of the discovery of a criminal's dead body in his own bed.

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.