In an effort to find the site of an ancient Baku civilization, writer Ellen Marsten (Jean Byron), archer Bob Prentice (Bill Henry), and a trader named Santo turn to Olympic swimming champion and jungle guide Johnny Weissmuller (himself) for help. The safari is taken captive by the Moon Men, a pygmy tribe that worships the immortal high priestess Oma (Helene Stanton). Johnny struggles to free the captives in one of the final installments of the adventure...