A trio of seedy gangsters, Gigi, Totor and Jo, manage to snatch a suitcase of diamonds, which they promptly lose. The precious luggage is recovered by Ernest Mamourette, a distracted salesman. The police suspect him of being behind the hold-up and the safe. Gigi reappears under the identity of a certain Countess Olga and expresses her desire to marry Mamourette, who is released from prison, and is drawn into a burglary at the home of the real Countess, who, on the point of committing suicide, is reunited with Ernest, her beloved husband, whom she thought had disappeared.