The story:
A gang of drug smugglers makes a daring incursion across the U.S. border in a small plane, but is forced to land and find a hiding place fast. Settling for an abandoned mesa in the middle of the desert, they manage to land a helicopter on a narrow plateau at the top of the tall and imposing structure.

When the bandits break into the inner sanctum on the plateau, a radio signal is transmitted all the way to the Skull Cave at the other side of the Earth, where a worried owner immediately sets off to investigate the intrusion...