Frankenstein's unscrupulous colleague, Dr. Bohmer, plans to transplant Ygor's brain so he can rule the world using the monster's body, but the plan goes sour when he turns malevolent and goes on a rampage.
Bradley and sidekick Sharpe are sent west to investigate the murders of pony express riders who are being killed to prevent the Spanish Land Grant papers going to Washington for registration.
Wild Bill Hickok, Calamity Jane and Buffalo Bill go up against Indians and a gunrunner.