Fremont, a stock-broker, plays poker; his wife is a bridge friend; their son Carl inherits a craving for card playing, for which he neglects his studies, his business, and his sweetheart, Nita. Carl asks his father for money, and is told that no more gambling debts will be paid for him or his mother. His mother overhears this, and takes money from her husband to pay a gambling debt. Carl is accused of the theft, shields his mother and is cast out. As Nita bids him good-bye, his friend and classmate, Zimar, invites him to accompany him to India. Carl declines. A year later the ragged Carl wanders the streets, his gambling passion stronger than ever. He is knocked down by a man, who, sorry for his action, tosses him money. With this, Carl wins more money, which he gives a poor woman in a generous spirit. His studies completed, Zimar returns and gives an exhibition of his hypnotic power by curing Nita's headache. He proposes, and when Nita tells him she loves only Carl, the noble Zimar tells her he will cure Carl and make him worthy. Carl is located by the crystal. Unable to borrow money with which to gamble, Carl robs the poor woman of the money he gave her, and is captured by her husband. Nita and Zimar appear, and Carl is hypnotized and taken home, where Nita makes the parents realize their responsibility for Carl's passion. Zimar tells them he will cure this craving by causing Carl to experience a gambler's hell. In a hypnotic trance, Carl plays cards with Nita and his parents, and Nita wins. Carl creeps to her room, steals her winnings, and when she awakes, stabs her. Her body changed to the Queen of Hearts. He flees, and is intercepted by his parents, whom he also stabs. He gambles with Nita's winnings, and draws the Queen of Hearts, which changes to a picture of the dead Nita. He finds Nita in his nurse, after he has become a maniac. He finds Nita and his parents in the death chair, and in the final horror, finds Hell's flames full of playing cards which assume their forms. And in the end of the terrible trance, Carl and his mother are senseless and Zimar announces that they are cured. Nita, believing fully in Zimar's power, is perfectly willing to marry Carl.