Jonny and Hadji are marooned (by shipwreck) on the jungle coast of the African continent, where they are adopted by a tribe of friendly brown gorilla-like apes who protect them from a pair of Australian poachers, intent on kidnapping them for ransom. When the poachers managed to abduct Dr. Quest and Race, Jonny and Hadji must persuade to the apes to help rescue them and defeat the poachers.
After an emergency landing in the Andes Mountains, Race is challenged to an aerial dogfight by Baron Heinrich von Frohleich, an old German fighter ace of World War I fame (who keeps a collection of vintage aircraft at his Bavarian-style castle in South America). The Baron's machine guns, however, are loaded — Race's are not.