Le système du docteur Terrier

À vous de jouer, monsieur Vidocq !

Vidocq and Annette return to Paris, where they plan to hide out with Gibassier, Vidocq's former comrade and blackmailer. But when they arrive, Gibassier is dead and Vidocq is arrested for his murder. He escapes and returns several times to M. Henry, chief of the Paris police, to obtain permission to find the real culprit himself. Disguised as Gibassier, he waits for the murderer to return to finish the job...