A female vampire adopts a series of fake identities to enter the homes of aristocratic families and prey on their daughters. A general whose own daughter has fallen victim to the bloodsucker pursues her, determined to end her reign of terror. Hammer horror based on a novel by J Sheridan Le Fanu, starring Peter Cushing, Ingrid Pitt and Kate O'Mara.

In the heart of Styria the Karnstein Family, even after their mortal deaths, rise from their tombs spreading evil in the countryside in their lust for fresh blood. Baron Hartog whose family are all victims of Karnstein vampirism, opens their graves and drives a stake through their diabolical hearts. One grave he cannot locate is that of the legendary beautiful Mircalla Karnstein. Years of peace follow that grisly night until Mircalla reappears to avenge her family's decimation and satisfy her desire for blood.