Dr. Mabuse and his organization of criminals are in the process of completing their latest scheme, a theft of information that will allow Mabuse to make huge profits on the stock exchange. Afterwards, Mabuse disguises himself and attends the Folies Bergères show, where Cara Carozza, the main attraction of the show, passes him information on Mabuse's next intended victim, the young millionaire Edgar Hull. Mabuse then uses psychic manipulation to lure Hull into a card game where he loses heavily. When Police Commissioner von Wenk begins an investigation of this mysterious crime spree, he has little to go on, and he needs to find someone who can help him.

The sinister Count Oetsch scandalizes the aristocratic social gathering at Castle Vogelod as he announces his intention to "crash" the festivities. Baroness Safferstätt is expected shortly, and the guests are well-aware of the rumors that Count Oetsch murdered the baroness' late husband. Oetsch refuses to leave, vowing that he will reveal the identity of the real killer. Before the weekend is through, the Count and Baroness will reveal secrets too shocking to be believed!

Lorenz Lubota is a city clerk with no direction in life. One day on his way to work he is run over by a woman driving a chariot and he is immediately infatuated with her.

Doctor Mabuse is a criminal mastermind, doctor of psychology, and master of disguise, armed with the powers of hypnosis and mind control, who oversees the counterfeiting and gambling rackets of the Berlin underworld. He visits gambling dens by night under various guises and aliases, using the power of suggestion to win at cards and finance his plans.

As the police intensify their bemusing search on Doctor Mabuse's notorious band of gangsters, the deceptive, elusive hypnotist Mabuse simultaneously begins to close in on himself.