A film projectionist longs to be a detective, and puts his meager skills to work when he is framed by a rival for stealing his girlfriend's father's pocketwatch.

The rise and inevitable fall of an amoral but naive young woman whose insouciant eroticism inspires lust and violence in those around her.

The heavily indebted baron Henrik von Hagen, who loves women and partying, learns that his former lover, Russian ballerina Madame Vera Vasiljevna, will be visiting Finland. They are reunited and sparks fly. But Vasiljevna's new hobby casts a shadow over their romance.

Francis, a young man, recalls in his memory the horrible experiences he and his fiancée Jane recently went through. Francis and his friend Alan visit The Cabinet of Dr. Caligari, an exhibit where the mysterious doctor shows the somnambulist Cesare, and awakens him for some moments from his death-like sleep.

Joe Ryan, a veteran train engineer, is demoted to a flagman position after a disastrous crash-- one caused by his cowardly and opportunistic partner. Though Ryan's failing eyesight is named as the cause of the crash, he's undeterred as he designs an automatic braking invention.

Charlotte Baker is drugged and taken to a brothel by Paul, her fiance, who in reality is a pimp. To find her, Charlotte's family contacts the celebrated detective Bob Macauley.

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.

After the train station clerk is assaulted and left bound and gagged, then the departing train and its passengers robbed, a posse goes in hot pursuit of the fleeing bandits.

Six burglars separately break into the Vickers mansion on Long Island to loot the safe but catch each other in the act. They all pretend to be members of the household when locked in by a well meaning police officer.

Charles Abbott is implicated in the death of his friend Escobar, brother to the woman he loves.

At a party thrown at the Metcalf estate, the Marquise D'Irancy's Sultana diamond disappears when the lights go out during a power failure. Suspected of the crime is William Kirkland, the wastrel son of the wealthy Kirkland family, but William's sister Diana comes to his defense. Aiding her in the investigation is Clamp, a wandering peddler.

Professional forger Bill Butters realizes one day that the police are closing in on him, and convinces his daughter Peggy to flee.