The Return of Dr. Mabuse

An Interpol courier is found murdered in a railway tunnel. He is carrying an attache case that supposedly contains proof of the Chicago Syndicate's planned cooperation with a European crime group; the case is missing from his body. Inspector Lohmann is pulled from his fishing holiday to pursue this lead.

From Washington, Lohmann learns that Mrs. Pizarro, a female representative of the Syndicate, is currently in Europe to meet with European criminals. The Federal Bureau of Investigation is sending Special Agent Joe Como to liaise with German authorities. These developments set the stage for a transatlantic crime network converging on Europe.

Lohmann meets Alberto Sandro, an imprisoned member of the European crime organization, in an attempt to learn more about the Syndicate's plans. The meeting is short and largely uninformative, providing only fragments of information. The search for the crucial link continues.

Mrs. Pizarro is murdered by a flamethrower, and Inspector Lohmann dodges questions from a nearby female reporter, Maria Sabrehm, with Joe Como at the scene. The sensational murder sharpens the investigation by tying the Syndicate to Mabuse's criminal network. The scene sets off a hunt for further clues.

The only witness is a blind man who recalls the distinctive sound of a man with a wooden leg just before the heat from the flamethrower hits. His testimony hints at the killer's identity and points investigators toward Sandro and the prison connection. The murder scene becomes the first major clue in the larger conspiracy.

Lohmann discovers a charred book on Mrs. Pizarro's body titled The Devil's Anatomy by Reverend Briefenstein of St. Thomas Church. The book lays out Mabuse's idea that the Devil can manifest by occupying human bodies, sometimes as a werewolf or vampire or even Mabuse himself. This discovery links the case to Mabuse's legacy and explains the strange phenomena surrounding the murders.

Lohmann, accompanied by Como and Maria, visits the Pastor at St. Thomas Church to ask about Dr. Mabuse, whom many believe is dead. The Pastor explains that a man's body can die while his soul can infest other men, suggesting a supernatural or mind-control channel for Mabuse's return. The church setting heightens the tension as the investigation tightens around Mabuse.

The voice of Dr. Mabuse comes over the church's speaker system, warning Lohmann to stop his investigation. Joe Como engages Mabuse in conversation and reveals that he is really Nick Scappio, a Chicago Syndicate representative there to negotiate a shipment of a new drug. The Syndicate demands proof of the drug's power before agreeing to cooperate.

Following a lead, Lohmann seeks out the blind witness, who is run over and killed. The pursuit of the killer intensifies as investigators realize a deliberate conspiracy is at work. The trail now points toward Sandro's escape and the prison's hidden network.

Como and Lohmann recapture Alberto Sandro, only to learn that the man in Sandro's cell is the dead man with a wooden leg described by the blind witness. The prison authorities deny that Sandro has left the facility, insisting he is sedated in his cell. The apparent deception reveals a deeper layer of Mabuse's control over the prison system.

Investigators realize Mabuse's drug is a mind-control device enabling criminals to be turned into 'zombies' and moved around by radio transmissions. Mabuse's network can be commanded to commit crimes with no recollection by the controlled individuals. The drug's power explains the prisoners' sudden loyalty shifts and disappearances from the prison.

Crucially, Mabuse's drug is said to be invented by Maria's father, a scientist who is a prisoner in the same prison as Sandro. Mabuse's grip extends beyond the prison walls to a planned assault by an army of drug-controlled criminals. The date of the plan is Friday the 13th, the film's premiere date, when the drugged prisoners would attack a nearby nuclear power plant.