The evil Queen Tenefi, who's usurped the throne of Memphis, demands that a steady supply of young women be sacrificed to the God of Fire inside the Mountain of Thunder. Maciste intervenes and saves from this sacrifice a village's women including the beautiful Antea. Maciste then becomes involved in an effort to restore to the throne of Memphis its rightful ruler, Prince Iram. To accomplish this task Maciste travels to Memphis but is betrayed by the silk merchant, Omnes. The Queen's soldiers capture Maciste and he's forced to undergo a Trial of Strength in which two teams of horses try to pull him apart. Impressed by his beauty and strength, the Queen calls an end to the Trial and then touches Maciste with her magic scepter which erases his memories and places him under her power. A female oracle then gives Antea a dart which, when fired into Maciste, will restore him to his senses. Antea sneaks into the Queen's palace, successfully uses the dart, but falls into the hands of the Queen who orders her to be sacrificed in the Mountain of Thunder. Maciste hears of this, enters the mountain, and rescues Antea just before the mountain explodes and puts an end to the reign of Queen Tenefi.