Steve Ranson, an ex-Texas Ranger, is called upon by Gregory Banion, manager of the Trans-Western Railroad, to solve a series of mysterious attacks on the railroad's surveying parties along the Ranahan Trail, Jeff Carson, owner of the stage line which will lose business when the railroad is completed, is the primary suspect. Steve, as the Durango Kid, foils an attempt on Carson's life and believes him when he says he is not responsible for the raids. They join forces and, with the aid of town gunsmith Smiley, they uncover the real outlaw leader.