George Ardisson

Upon his return from battle in the previous film, the great warrior Hercules learns that his lover, Daianara, has lost her senses. Acording of the oracle Medea, Dianara's only hope is the Stone of Forgetfulness which lies deep in the realm of Hades. Hercules, with two companions, Theseus and Telemachus, embarks on a dangerous quest for the stone, while he is unaware that Dianara's guardian, King Lico, is the one responsible for her condition and plots to have the girl for himself as his bride upon her revival.

In a 15th-century feudal village, a woman is accused of witchcraft and put to death. Her beautiful older daughter knows the real reason for the execution lies in the lord's sexual desire for her mother. After confronting the lord on the matter, she, too, is killed. A much younger daughter is spared and taken in by her mother's killers. Once she is of age, as a horrible, deadly plague sweeps the land, she marries the lord's worthless son. Then, during a brutal thunderstorm, the older daughter mysteriously reappears and begins to avenge her mother's death.