A plane flying to Cape Town, carrying a young couple and their baby, crashes in the jungle. Everyone on the plane dies, except for the baby who is rescued by Cheeta, Tarzan's Common chimpanzee. Tarzan and Jane adopt the child and name him "Boy." Five years later, a search party comes looking for Boy, because he is the heir to the Greystoke family fortune worth millions. The search party is led by the Lancing family, who are distant cousins of Greystoke. Tarzan and Jane claim the child is dead and that Boy is theirs, but the elder Lancing, Sir Thomas, recognizes Boy's eyes. The younger Lancings suggest leaving Boy and taking the inheritance. When Sir Thomas objects, they say they will take him back and, as legal guardians, still control the inheritance. Sir Thomas says he'll tell Tarzan, but the rest of the party imprison Sir Thomas in a tent and plan to abduct Boy. Tarzan overhears them plotting; he steals their guns and throws them into a deep lake. Jane arrives the next day and learns what has taken place, and admits that Boy is Greystoke. She persuades Tarzan to retrieve the cache of guns, without which the search party can't survive. Tarzan retrieves them but Jane drops the rope so that Tarzan is trapped.