Seasoned criminal Doctor Mabuse (Rudolf Klein Rogge) has been locked in an asylum for the past 10 years, straddling the line between life and death. One of his last projects involves a mysterious manifesto that sets in place a crime-filled future. Discovering that the creepy article's text seems to predict disturbing events, detective Lohmann (Otto Wernicke) tries to put together the pieces of this mind-bending case.