After Phil Guard and Normandin capture two Vampires, Irma Vep and Moreno, the latter is guillotined and the woman is condemned to life imprisonment. The authorities as well as Philip, good reporter that he was, were lulled into security, thinking the Vampires were now powerless. They did not even know about Satanas, who was now leader of the band. Before her incarceration for life, Irma Vep is sent by the authorities to Algeria to testify regarding a crime committed there. Before leaving the detention home to board the vessel, she receives comforting information from a priest. The man is really Satanas in disguise. Satanas tells her that once on shipboard she must feign illness and be sent to the infirmary near the stern of the vessel, with his wonderful electric gun Satanas will destroy the ship, the projectile striking near the bow. Thus Irma will have a chance to regain her liberty. Even if she dies, that will be better than a life spent in prison. The ship is destroyed and Irma Vep is saved. She does not find Satanas, being afraid to disclose her identity in Algeria. She works her way back to Paris, whither Satanas has also returned. The head of the Vampires plans to destroy Philip Guard. The reporter is bound and gagged in his room and left to wait for the explosion of a bomb which will destroy him and those dear to him. Fortunately Normandin arrives, hears the clock-work tick of the infernal machine, and throws it into the garden just in time to save Philip. Satanas is living as a wealthy man in a new apartment, but the faithful Normandin penetrates his disguise and finds one of the shells for the electric gun. Normandin is accompanied by his son who enters the apartment upon a pretext. When he thinks he is alone he admits his father. Normandin hides in a chest, a fact known to Satanas, who has been watching through a mask on the wall, which is really a peep-hole from another room. The boy and Satanas struggle, after the former sees the chest locked and fears that his father is to be smothered. The fight is going in favor of the Vampire, despite his young adversary’s revolver, when the door is broken and Philip and the police enter. Satanas is overcome and Normandin is released. He is suffering from a slight wound. His own son has shot him, grazing his big nose! The Vampires hold a meeting to discuss the capture of their chief. Irma Vep appears for the first time after her return and is loudly welcomed by the band. Venenos, the “man of poisons,” takes from his pocket directions Satanas left with him in case he was captured. The request is for a certain letter to be smuggled to him in prison. This is done. Satanas chews the letter into a pulp and drops dead. The paper has been steeped in a deadly poison.