Oscar's disappearance, after being last heard from in Las Vegas, sends Steve to the desert where the government operates a gold mine. Indications are that Oscar is involved in a plot to steal the gold, and Steve's determination to learn the truth takes him to the mine to find Oscar. After a rescue attempt fails, Steve is forced to toil in the mine against his will. Meanwhile, an old friend of Oscar, Bert Carrington, an official in the Mining and Research Bureau, arrives with plans to smuggle the gold (valued at $25 million) out of the country--and he makes a tempting offer to Oscar for the use of a government plane. Steve evades his captors and races to the rescue.