Tarzan travels to South America at the request of his old friend, a Professor who believes an ancient cult is preying on the local native population. He soon dons his loincloth and with Cheetah and pet lion Baron travels up the Amazon river. He meets up with Captain Sam Bishop and his young ward Pepe and all of them are soon in the hunt for the Jaguar Men and their leader Barcuna. Tarzan rescues a pretty doctor, Ann Phillips, after her jungle hospital is burned to the ground. Together, they set off into the jungle to confront the cultists who are enslaving the local population.