A 1940 Roy Rogers Western. During the American Civil War a Confederate officer who is also a Captain in the Union Cavalry is keeping Federal troops in the Colorado Territory from reinforcing their armies in the East by forming an alliance of secessionists, outlaws, and opportunists as well as arming hostile Indians. Unable to send more reinforcements, the United States Secret Service sends one man, Military intelligence officer Lieutenant Jerry Burke (Roy Rogers) to identify who is behind the troubles and put an end to it. Armed with a sweeping letter of both law enforcement and military powers signed by President Abraham Lincoln Jerry meets his old comrade in arms Gabby to go west. The Confederate/Union officer calling himself Donald Mason is actually Jerry's brother Donald. Donald escapes arrest but confronts his alliance that they are getting rich whilst he is doing all the work and facing all the danger. Donald takes over by shooting a corrupt Indian Affairs commissioner after informing him that the agent is no longer an asset but a liability. Donald saves his brother's life and is repaid by Jerry by allowing him to face his end by leyde fuga (getting shot while escaping) instead of hanging after Jerry captures him.