When the unscrupulous Carlos Manning discovers that an old Spanish land grant recently unearthed will leave a huge section of California real estate to the heirs of Don Quantero, he…

Claire Forrest seeks her kidnapped scientist father, hidden somewhere on Mystery Island. He is held and forced to work on diabolical inventions by Captain Mephisto, a costumed villain.

El Malo, notorious Mexican bandit, forces the Mayor of Sierra Blanca, Seth Landport, to open the safe and turn over to him 2,000 pesos, which the bandit gives a promissory…