The story tells of the reformation of a millionaire's son, who later develops such consistent speed on the "draw" and on a horse that it wins for him the title of "The Blue Streak." Driven from home, the "Streak" changes his mode of living entirely. News of his adventurous spirit penetrates even into the town of Sterling, beyond the Rockies, where he one day finds himself. He strolls into the common meeting-place there, the saloon, and proceeds to prevent a forced marriage between the proprietor's daughter, "The Fledgling," and a gambler by the simple expedient of covering all with his revolver while preparing to make her captive himself.

The townspeople of Purity despise Martin Bradley because of his heavy drinking, but he still does his best to make life better for the town. He helps to support two women who have been socially ostracized by the townspeople, and during the election campaign for mayor, exposes the corruption and dirty tricks of candidate James Durkel, resulting in the election of his opponent Chester Thorndyke. However, the voters of Purity insist that Thorndyake disavow his ties to Bradley, whom they regard as disreputable.