Sergeant O'Malley, a member of the Northwest Mounted Police, is assigned to bring in the murderer of a saloon keeper named La Grange. Disguised as a cowboy, O'Malley attends a rodeo, where he believes a group of outlaws, including the alleged killer, are performing. He follows them to their stronghold in the mountains, then robs a bank in order to ingratiate himself into the gang. After making off with $5000, he is chased by a posse, but he manages to elude them, and then is admitted into the gang. O'Malley falls for Rose Lanier, who cooks for the gang. Rose's brother, Bud, is the alleged killer. When the leader of the gang, Red Jaeger, makes unwanted advances towards Rose, O'Malley thrashes him. Jaeger decides to betray the gang, and secretly rides to the sheriff's office. There, he learns that the stolen bank money has been returned, and that O'Malley is working undercover. Jaeger shows the evidence to the gang, and they tie O'Malley to a tree. He is placed under guard, and is set to be hanged at daybreak. Rose secretly gives O'Malley a knife, enabling him to escape, along with her and her brother. While the three are on the run, O'Malley learns that Bud killed La Grange because the saloon keeper had wronged Rose. Later, O'Malley leaves a note telling Rose and Lanier who he really is. He also informs then he is headed back to his post to resign, but will return for Rose if she is willing to wait for him.