Workers land an aircraft in the jungles of Africa in search of lions for their circus. While trapping lions, the three men meet with Tarzan (Johnny Weissmuller), Jane (Maureen O'Sullivan) and their adopted son Boy (Johnny Sheffield). Watching Boy's tricks with the elephants, the head of the circus, Buck Rand (Charles Bickford), realizes that Boy would be a great act for the circus. The group is attacked by natives, and it appears that Tarzan and Jane have perished in a jungle fire. The men take Boy on their aircraft and return to the United States. Tarzan's loyal chimp Cheeta wakes Tarzan and Jane before they are burned-to-death by the fire. Cheeta tells Tarzan that Boy has left with the men on their aircraft.