Fritz Lang directed this sequel to his nearly four-hour Dr. Mabuse silent of 1922 (often shown in two parts, Dr. Mabuse: Der Spieler/The Gambler and Dr. Mabuse: King of Crime). The film opens with Detective Hofmeister (Karl Meixner) spying on the activities of a criminal syndicate. Not realizing he has been seen, Hofmeister is attacked by the thugs and later turns up out of his mind. He is placed in the institution of Professor Baum (Oscar Beregi), who becomes increasingly obsessed with another patient -- the master criminal and hypnotist Dr. Mabuse (Rudolf Klein-Rogge). Baum's assistant, Dr. Kramm (Theodor Loos), connects Mabuse's writings to a series of the syndicate's recent criminal activities, and is murdered for his knowledge by crime lord Hardy (Rudolf Schündler) who takes orders from a hidden Mabuse. Putting all these pieces together is chief investigator Lohmann (Otto Wernicke), whose story plays out simultaneously with that of ex-cop Thomas Kent (Gustav Diessl), a member of the gang who is torn between his need for money and his love for a young woman named Lilli (Wera Liessem). Various clues lead Lohmann to suspect Mabuse's involvement, but when he arrives at the asylum, Baum reveals that Mabuse has died. Meanwhile, Kent's decision to confess to the cops lands himself and Lilli in a room with a hidden bomb. Lohmann traps the gang in a moll's house, leading to a wild shootout. Kent and Lilli escape and race to Lohmann to tell him that Mabuse is behind the crimes. They all race back to the asylum where they discover that Mabuse has taken control of Baum, who sets a monstrous fire at a chemical factory. The mad doctor then leads Lohmann and Kent on a wild car chase back to the asylum where the mystery behind the Baum-Mabuse-Hofmeister connection takes a disturbing turn.
by Patrick Legare synopsis