A British lord raised by apes kidnaps a beautiful noblewoman exploring Africa with her father.

English trader James Parker and his partner, Harry Holt, are about to embark on a journey beyond the Mutia Escarpment, where a fabled ivory-rich elephants' graveyard lies, when James's daughter Jane arrives from England. After a tearful reunion with her father, Jane, who says she is "through with civilization" and prefers to be a savage, insists on joining the expedition on its dangerous trek in search of an ivory deposit worth eleven million dollars. Though James is reluctant to let his daughter accompany them, he eventually allows her to go when a smitten Harry sides with her. Before they leave, James tells his daughter about the legend surrounding the burial site, and warns her that the natives consider the place sacred and taboo and that all who so much as look at it are put to death by tribal witchmen. James's account of the legend soon proves true when a native, crazy with fear after having seen the burial ground, runs into their camp to take refuge from the brutal Ubangi tribe and then mysteriously dies. When the expedition party finally arrives at the wall of the Mutia Escarpment, they are forced to scale its narrow precipice, which proves too narrow for one of the men, who falls to his death. Jane also loses her footing, but she is pulled back by a rope. After coming to a resting point, the expedition party is bewildered by an ape call they hear in the distance that is distinctly human-like. They soon meet the source of the sound when Tarzan uses his jungle call to save them from an attack by threatening hippopotami. Tarzan, who understands no language, then carries the screaming Jane to his treetop home, where she gradually loses her fear of him and the apes who live in the trees. Later, while Tarzan has left Jane to search for food, Harry and James rescue her, but not before Harry shoots an ape that he believes is a threat to Jane. Tarzan witnesses the killing and follows the expedition to take revenge on them. After drowning one of James's African guides, Tarzan recaptures Jane and then, with the help of an elephant, engages an attacking lion in a fight. The elephant carries the defeated and unconscious Tarzan to safety and then calls Tarzan's apes to summon Jane. Jane arrives in time to bandage the wounded ape man, and the two share a romantic swim in a nearby river. Later, from her treetop vantage point, Jane sees her ailing father fall down and decides that she must go to him. Tarzan, hurt by Jane's departure, flees into the jungle. Soon after he leaves, the expedition is surrounded by a large number of pygmies, who abduct the hunters and take them downriver to their camp. Along the way, Jane sees Cheetah, Tarzan's chimpanzee friend, and sends the animal for help. While the pygmies make a cruel game out of sacrificing Harry, James and Jane to a ferocious beast in a pit, Tarzan arrives with a herd of elephants, and Jane and her party are freed. Jane, her father, Tarzan and Harry ride away from the camp on the backs of elephants, and though James discovers that his elephant is dying, he insists on staying on him in the hope that the animal will lead him to the sacred burial site. The elephant leads James to the site, but as soon as he sets his eyes on the grave, he dies. After saying goodbye to Harry, Jane is reunited with Tarzan and Cheetah and remains with them.