Bob McGuire, Royal Northwest Mounted officer trailing a ring of opium smugglers, suspects gambling house proprietor Big Bill Lusk. Lusk's plan is to frame McGuire by drugging him and marrying him to Katie Peck, a dance hall girl who knows the plot. McGuire's superior officer is killed, and McGuire is accused of the murder; but Katie, who has fallen in love with McGuire, discloses that Lusk is the murderer and exposes the smugglers' plot.