In the Flash Gordon radio episode Rules Over Cave World, Flash, Dale, and Dr. Zarkov journey deep beneath the planet Mongo to a mysterious underground realm known as Cave World. There, Flash confronts a tyrannical ruler who oppresses the cave dwellers with fear and violence. Using courage, quick thinking, and advanced technology, Flash leads a daring rebellion to free the people and restore peace. The episode blends science fiction adventure with heroic action, capturing the spirit of classic space opera storytelling.