Fabius, a Roman liberto married to an Egyptian woman, is falsely accused of treason and condemned to death. His baby son saves himself thanks to a white lioness who takes care about him. Emperor decides to exile all of exponents of Mitra Cult, after Mitra's High Priest talks about a prophecy of doom. According the prophecy, evil forces will destroy the emperor's nephew if the chosen isn't there to protect him. The chosen is a dark-skinned boy with a fair-skinned mother.