U. S. Cavalry Lieutenant Ranson belittles the exploits of a bandit known as "The Red Rider," and boasts to his fellow officers that he could hold up a stagecoach with a pair of scissors. And rides out and does so. But the next day, the postmaster, returning from a neighboring town, is also held up and his bodyguard is killed. Ranson is arrested on suspicion and placed on trial. But at the trial suspicion point to Cahill, post trader, and father of Ranson's sweetheart, Mary. In order to save him, Ranson pleads guilty but, in return and knowing that his daughter loves Ranson, Cahill admits he is "The Red Rider." Meanwhile, the real "Red Rider" is still at large.