Although Count Dracula was destroyed by Van Helsing (Edward Van Sloan), who is now being tried for his murder, Dracula's daughter, the Countess Marya Zaleska (Gloria Holden), is still alive -- and her father's death has brought her no closer to eradicating her vampiric thirst for blood. When attempts to free herself of the disease fail, she turns to psychiatrist Dr. Garth (Otto Kruger) for assistance, but soon finds herself struggling with the desire to make him one of the undead as well.