A woman is killed in a locked room, and her daughter Susan confesses to the murder after apparently becoming possessed by the spirit of her long-dead younger brother. The Chief enlists a psychic to help him in his investigations, but the clues that she offers him seem to confuse more than they assist.

The Chief links his case with a psychiatrist, who turns out to be a psychopath with a passion for brainwashing. Before he can get his evidence together, however, Fran is taken as the next victim of the doctor's peculiar brand of therapy, and is programmed to kill Ironside. Meanwhile Susan has to face past guilt over the death of her brother before she can be safe from herself.