When her older sister Jacqueline disappears, Mary Gibson is forced to leave her private school to look for her in New York City. A bit naive and out of her depth, she is not quite sure how to go about finding her. Eventually she meets Gregory Ward, her sister’s husband and a mysterious psychiatrist, and Dr. Louis Judd, who claims to know of Jacqueline’s whereabouts. What she doesn’t realize is that her sister became involved with devil worshipers who now want to eliminate her for having revealed their existence.