After Greek fisherman Demetrios (Anthony Hall) rescues Princess Antillia (Joyce Taylor) at sea, he returns her to her home country of Atlantis. Once there, he is enslaved due to the evil machinations of Zaren (John Dall). Using sorcery, Zaren has made the inhabitants of Atlantis into slaves for mining crystals, which will then be used for a death ray to take over the world. Demetrios finds an allay in Azor (Edward Platt), a high priest who helps fight back against Zaren.