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. His wife has read the murderer’s description in the Yuma Gulch paper and the offer of a $1,000 reward. She suspects her husband, and, when in an altercation with her, she becomes convinced of his guilt, she writes to Sheriff Gordon and gives the information necessary to arrest Benson. She posts the letter with Jack, when he rides by, and her husband suspects what she has done and wrings a confession from her. He knows that his only hope of freedom lies in intercepting the letter, and so follows Jack to the turning point in his daily trip, where he is wont to change horses and dine at the home of George Stone, whose daughter, May, he expects to make his wife. Benson comes while Jack is eating, and succeeds in slipping a sleeping potion in the latter’s coffee. Jack falls asleep, but before Benson has an opportunity to extract the letter from the mail sack. May returns and, being unable to arouse her sweetheart, she rides with the mail back to Yuma Gulch. Benson follows in his endeavor to get the letter, and when he decides that the chase is hopeless, returns to his cabin, collects the small hoard he has there and rides for the mountains and freedom. In the meantime the letter has been delivered to Sheriff Gordon and he sets out with a posse to capture Benson. Jack, who has recovered, joins them on the way, and after a long chase, they come upon the wounded Benson and arrest him. Jack is deeply grateful for the services rendered him by his faithful sweetheart, and announces to the assembled cowboys his intention of making May his wife as soon as his father’s death is avenged.