When our picture opens, Joe Flynn, a rider in the service of the government, has been shot from ambush by a masked man and is dying. Grouped at his bedside are his son Jack, a sturdy young man, the local doctor and the county sheriff. The old man dies and a week later we see Jack delivering the mail. The sheriff has inserted the description of the murderer in the Yuma Gulch Herald, and the country is being scoured to find him. Jack has a long and perilous ride between the two points of his route and is frequently beset with danger. Steve Benson, a desperado, who has killed old man Flynn, is living unhappily with his wife in hourly fear of having his crime discovered.