Synopsis by Hans J. Wollstein
About to be sacrificed to the Sun God by La's (Kithnou) tribesmen, Tarzan (Frank Merrill), his mind still clouded from a bump to the head, is saved by the surprising arrival of Achmet Zek's band of Nomads, who once again abduct Lady Jane (Natalie Kingston). Not realizing that Jane is his wife, Tarzan's mind is instead occupied by the memory of the "pretty pebbles," the Jewels of Opar, stolen by Werper (Al Ferguson), who pretended to be Tarzan's friend. From high in the treetops, the jungle man observes a fight to the death between Werper and Zek, the greedy European emerging victorious. Back at the Greystoke plantation, now in the hands of the Nomads, Werper tells Zek's second-in-command, Mohammed Beyd (Paul Panzer), that the chieftain died in an accident. Instant friends, the two villains decide to sell Jane at the slave market. The friendship, however, lasts only until Beyd attempts to ravage the white girl. The chieftain-to-be is killed during the struggle and Werper blames Tarzan, who has arrived to regain possession of the jewels. Outnumbered by the angry Nomads, Tarzan is forced to the ground.