During the Civil War many Trailhead ranchers have been killed or driven from their land by a ruthless gang of raiders. The secret leader of the gang is Bill Sanger (James Nolan), who poses as a rancher but is actually the head man of an eastern syndicate seeking to buy up the land through which railroads will be constructed at the war's end. Learning the newspaper publisher John Thornton (Jason Robards Sr.)has received a letter giving away the agenda of Sanger, and the latter kills Tornton, and then manages to cast the suspicion of the gang activities upon the dead man and his son, Frank (Jay Kirby) whom the gang has kidnapped. U. S. Marshal Monte Hale (Monte Hale)is convinced of the Thronton's innocence but finds himself opposed by the citizens and ranchers with the exception of Eli Walker (Paul Hurst), and Cathy Thornton (Pamela Blake), daughter of John and sister of Frank.