The fourth in the MGM Tarzan series to feature Johnny Weissmuller as the "King of the Apes." 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 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 a fortune worth millions. Jane tries to help the search party and Boy go back to civilization, against Tarzan's wishes.