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.

Outside Denver, Colorado, Beau and his friend, Judge Scott, find shelter during a blizzard at the home of Martha Flood and her niece Sally. Martha and the judge are plotting to institutionalize Sally in order to take over her inheritance. However, Martha's lover, a professional killer named Chet Whitehead plans to kill Sally, the judge, and Maverick.