Dr Brooks (E. Alyn Warren) is captured by followers of Zar God of the Jewelled Fingers but he is soon rescued from their lost city by Tarzan (Buster Crabbe) a white man who was raised in the jungle by apes and speaks no English just a grunt from time to time. But Tarzan undertakes to locate Brooks' daughter Mary after seeing a photograph of her. Meanwhile back in the jungle Mary and Bob Hall (Edward Woods) are searching for her father. Their guides Jeff (Philo McCullough) and Nick (Matthew Betz) are more interested in finding the treasure of Zar and scoring with Mary than finding Dr Brooks. Jeff is in possession of a message offering a large reward for Tarzan...dead or alive.
