Beau Maverick wins half-ownership in the Blue Bell Saloon in Arizona. In an attempt to raise funds for the floundering business, Beau and his partner Charlotte become partners with a mysterious gold prospector known only as the Dutchman. Along the trail to Superstition Mountain where the gold is located, Beau, Charlotte, and the Dutchman encounter danger in various forms.

Con artist Ferguson knocks Beau Maverick unconscious during an unsuccessful attempt to hoist a priceless diamond necklace from a French countess. Ferguson claims that the countess' diamond is fake and that he was in the process of replacing it with the real thing when Beau startled him. Ferguson offers Maverick $5,000 to switch diamonds. Beau is being set up for robbery by Ferguson and his equally devious wife.