In the opening chapter of Fantômas, entitled "The Genius of Crime," a chilling conversation at the secluded Château de Beaulieu introduces a wave of terror and the shadowy, shape-shifting criminal mastermind. The elderly Marquise de Langrune hosts a dinner where guests discuss the inexplicable crimes plaguing Europe.

The chapter concludes with a sense of pure, suffocating dread as young Charles Rambert experiences intense fear and hears strange sounds in the night, setting the stage for the tragedy to come.