In Alberta, Canada, a Cornish emigrant unmasks a rustler posing as the girl's "blind" father.

Young John Tresler arrives at an area of the Canadian Northwest that is terrorized by the Night Riders, a gang of marauders led by the mysterious Red Mask. Tresler falls in love with Diana Marbolt, the daughter of blind ranch owner Julian Marbolt, and begins to organize a posse to run down the Night Riders. Wounded in his first skirmish with the marauders, Tresler is nursed back to health by Diana, who is desired by Jake Harnach, Marbolt's bullying ranch foreman. Shot in a fight with Marbolt after he demands Diana's hand, Jake reveals the hideout of the Night Riders, and Tresler's posse and the North West Mounted Police finally destroy the criminal gang. Red Mask, who falls to his death from a cliff, turns out to be Marbolt, who is blind by day, but sees clearly by night. Tresler buys a ranch and marries Diana.—AFI