The coroner and scientist Dr. Warren Chapin is researching the shivering effect of fear with his assistant David Morris. Dr. Warren is introduced to Ollie Higgins, the relative of a criminal sentenced to the electric chair, while making the autopsy of the corpse, and he makes a comment about the tingler-effect to him. Ollie asks for a lift to Dr. Warner, and introduces his deaf-mute wife Martha Higgins, who manages a theater of their own. Dr. Warner returns home, where he lives with his unfaithful and evil wife Isabel Stevens Chapin and her sweet sister Lucy Stevens. Dr. Warner, upset with the situation with his wife, threatens and uses her as a subject of his experiment. When Martha dies of fear, Dr. Warner makes her autopsy and finds a creature that lives inside every human being, feeds with fear and is controlled by the scream. Once Martha was not able to scream, the tingler was not rendered harmless and became enormous. When the living being escapes, Dr. Warner and Ollie chase it in a crowded movie theater.