John Whyte arrives in America just in time for the Civil War and joins the Union side working directly for Abe Lincoln. His first assignment is with Alan Pinkerton who is trying to breakup a Confederate spy ring in the north. Lincoln is so impressed with John that he sends him out to work with General Grant and report to Lincoln whether the bad press Grant has been getting as a drunk and a butcher is justified.
John helped smash a Confederate spy ring and was rewarded with command of his own cavalry brigade. To his amazement, his old junior officer Lieutenant, George Custer, shows up as his commanding General. In the desperate fight at Gettysburg, John grudgingly accepts Custer for the military genius that he is. After mortally wounding the Grey Cavalier of the South Jeb Stuart at the battle of Yellow Tavern, John is also wounded. For his actions, he is awarded the Congressional Medal of Honor.
John Whyte, Pinkerton detective, war hero, and banished son of an English Earl, undertakes the difficult assignment of discovering who is responsible for a series of deadly gold shipment robberies. Along with his faithful servant and companion, Kahm Singh, a retired Sikh warrior, and assisted by Curly Bill Williams, a happy-go-lucky Texan, John travels to Denver in the company of Rafe Wallace, the man who hired the Pinkerton's in a desperate attempt to save his gold operations from a vicious gang of cutthroats.