This low-budget Spanish-Italian co-production was the handiwork of cult filmmaker Amando De Ossorio, best known for his series of Knights Templar zombie films which began with La Noche del Terror Ciego (1971). Faded '50s bombshell Anita Ekberg stars as Silvia, a young woman who travels to the family castle which she will soon inherit. When she arrives, she meets her uncle (Julian Ugarte), who gives her some rather disheartening news. Many years before, a nun named Malenka was burned as a witch in the town square and swore to return for revenge. Silvia looks just like Malenka, and the villagers are terrified that the witch's spirit has been reincarnated in her. Soon, villagers start dying, and Silvia is so sure that she is possessed that she breaks off her engagement, convinced that she is destined to kill her beloved (Gianni Medici). Naturally, as the title already gives away, the blood-drinking attacks are part of a plot by Ugarte to drive Silvia mad and steal her inheritance.