Captain Roger Drum (
Buster Crabbe) shoots down an enemy plane carrying microfilm while on its way to Africa to deliver it to an enemy of America. Intent on revealing this subversive group for whom the microfilm's message is intended, Drum assumes the enemy pilot's identity. He flies his twin-engine aircraft across the Atlantic, where he is forced to crash it in a remote African jungle. Drum is rescued by the all- female Rock People, led by Princess Pha. He is renamed Thunda, King of the Congo, after he repeatedly rings a temple gong using a large stone mallet, sounding the alarm to an attack by the primitive, all-male Cave Men. With the subversives believing Thunda is their missing pilot, and with the Rock People under constant attack from the Cave Men, Captain Drum plots to bring down the subversives who are searching for a new metal more radioactive and powerful than
Uranium. At the serial's conclusion, Thunda (Drum) clears the jungle of America's enemy and is able to reunite, as one tribe, the all-female Rock People and all-male Cave Men. ==Cast==