Philippe Guérande (Édouard Mathé), a reporter working for the newspaper "Mondial" who is investigating a criminal organisation called the Vampires, receives a telegram at work stating that the decapitated body of the national security agent in charge of the Vampire investigations, Inspector Durtal, was found in the swamps near Saint-Clement-Sur-Cher, with the head missing. Being turned down by the local magistrate (Thelès), he spends the night in a nearby castle owned by Dr. Nox (Jean Aymé), an old friend of his father, along with Mrs. Simpson (Rita Herlor), an American multimillionaire who desires the property...

Grand Vampire in disguise as Count de Noirmoutier, reads that ballerina Marfa Koutiloff (Stacia Napierkowska), who is engaged to Philippe, will perform a ballet called The Vampires. To prevent her from publicizing the Vampires' activities and to deter Philippe, he gives Marfa a poisoned ring before her performance, which kills her onstage. Amidst the panicking crowds Philippe recognizes the Grand Vampire and follows him to an abandoned fort and is captured by the gang. Then...

While faking illness to get off work, Philippe tries to decode a red booklet that he lifted from the Grand Inquisitor's body, which contains the crimes of the Vampires. He discovers that his house is under surveillance by the Vampires, so he leaves in disguise. Following clues in the booklet he arrives at "The Howling Cat" night club. Performing there is Irma Vep (Musidora), whose name Philippe sees is an anagram for vampire. Then....

The Grand Vampire, under the alias of a real estate broker "Treps", meets Juan-José Moréno (Fernand Herrmann), a businessman, who asks for an apartment with a safe. The Grand Vampire puts Moréno into an apartment whose safe is rigged to be opened from the rear through the party wall of an apartment belonging to Irma Vep and the Grand Vampire. Then...

A fortnight has passed since the events of Maillot. Moréno searches for clues that will lead him to the vampires, and reads in a newspaper that a Fontainebleau notary has been murdered by them; possessing a gaze with a terrible hypnotic power, he takes control of his new maid, Laura, to make her his slave. Meanwhile, Philippe and Mazamette watch a newsreel about the murder investigation, in which they see Irma Vep and the Great Vampire. They cycle to Fontainebleau to investigate .......

Irma is now a devoted collaborator of Venomous, who is set on getting rid of Philippe and Mazamette. He learns that Philippe is engaged to Jane Bremontier (Louise Lagrange), and the following day Irma and Lily Flower rent an apartment above hers. Irma's maid, a Vampire also, hears that Philippe and Jane's engagement party will be catered for by the famous Béchamel House. Then....