Leo Vincey, told by his dying uncle of a lost land visited 500 years ago by his ancestor, heads out with family friend Horace Holly to try to discover the land and its secret of immortality, said to be contained within a mystic fire. Picking up Tanya, a guide's daughter, in the frozen Russian arctic, they stumble upon Kor, revealed to be a hidden civilization ruled over by an immortal queen, called She, who believes Vincey is her long-lost lover John Vincey, Leo's ancestor.