Retired magician Diijon is disgusted when his wife Victoria works out a magic trick involving a guillotine with Sheffield, the owner of a magic shop. Despite the fact that he and Vicky have no money, Diijon prefers to devote himself to developing the powers of his mind and declares himself finished with simple trickery. When Vicky's old friend, musician Tony Holiday, arrives at Mrs. McGaffey's boarding house, where Diijon and Vicky also live, he is worried by Diijon's treatment of Vicky. Diijon's refusal to work drives Vicky to look for a job and when her search is unsuccessful, Tony offers to get Diijon a job performing in the same café where he and his friend Guzzo play in a gypsy band. Vicky begs Diijon to take the job and surprisingly, he agrees. In the opening of the act, Diijon hypnotizes Vicky, but when the trick fails, he accuses Tony of engineering the failure to make him look like a fool in front of Vicky. Tony blames the trick's failure on Diijon's recent lack of practice. After walking the streets for hours, Diijon goes into a diner for a cup of coffee. While he is there, a man tries to rob the café, but Diijon is able to hypnotize the man with the aid of a cigarette lighter and prevent the robbery. He practices the same technique on a newsboy with similar success. Delighted by his newly perfected ability, Diijon returns home to find Vicky and Tony breakfasting together. He assumes they are having an affair, which so angers Vicky that she leaves the marriage. Consumed with jealousy, Diijon then thinks about using his hypnotic powers to commit a murder. He practices first on Danton, the partner and husband of dancer Denise. Diijon orders the hypnotized Danton to write a suicide note and then drown himself. In the meantime, Vicky has taken a job singing with Tony's band. Diijon sneaks into Sheffield's store and loads a trick gun with real bullets. He then pays a surprise visit to Vicky's apartment and hypnotizes her. He instructs her to take the loaded gun from Sheffield's store and kill Tony after she performs her first number. Vicky does as Diijon orders, but accidentally takes the wrong gun, which is loaded with blanks. Realizing that Diijon is behind the incident, Tony calls the police, who trap Diijon at Sheffield's. A shootout ensues, and, in trying to escape, Diijon falls against the trick guillotine and is killed.