Fred Leroy is a wealthy industrialist, part of a large family-owned corporation. Fred has fallen for Annette, a comely cabaret bartender. He proposes to her, much to the horror of his family, which considers Annette and her unsophisticated father far below their caste. The family convinces Fred to give up the girl in exchange for increased position and income in the company. But Fred's lapse is momentary, and he again pursues Annette. But she, by this time, has learned of his erstwhile agreement and has agreed to marry someone else.

The Marquise de Langrune invites her friends at her castle in Beaulieu. Among them is Lord Beltham who also came to bring her a significant sum of money. The mysterious Fantômas kills the Marquise during the night. Inspector Juve is sent on his trail.