Criminal mastermind Fantômas, a man of a thousand faces, is unhappy with Fandor, a journalist who's written a fictive interview of him. He kidnaps Fandor, threatens to kill him, but first goes about ruining the journalist's reputation by committing a sensational crime in Fandor's guise. Hot on the trail is police Commissaire Juve, so Fantômas commits a crime looking like him. Soon, our intrepid heroes, Fandor and Juve, with the help of Fandor's girlfriend Hélène, are on the mastermind's trail, but who's in control?