Dave Harmon (Clint Walker) is a U.S. Marshal is sent to the territory of Yuma to bring justice to an otherwise lawless land. All previous marshals have been run out of the territory, mainly due to the actions of Arch King, a man who only works by his laws. The new marshal is set up for shooting a man and it appears that King and some U.S. soldiers are involved in the plot. Harmon is forced to defend himself and expose the corruption in Yuma.