Wolf Caulder is driven by childhood memories too terrible to forget, and by the words of Diego his Spanish rescuer. With his remaining eye Caulder sees frontier justice more keenly than many, and enforces it vengefully with his Colt revolver. The vengeance trail takes him in pursuit of a ruthless gang of train robbers who kill their victims in cold blood. Wolf is on the trail of the ringleader to exact his own brand of justice, and to free a lady driven by a similar revenge. His quest may prove fatal as his keen eye and fast gun are matched by an enemy unafraid to die.