Cisco, his amigo Pancho and the Sheriff fight a blistering running gun battle with outlaws Grant and Marsh. Plunging his horse, Diablo, directly into the killer's gunfire, Cisco cuts down Grant and wounds Marsh but not before an outlaw bullet kills the Sheriff. The wounded Marsh escapes to the home of the dead Sheriff, whose daughter June treats his wound. Cisco trails Marsh to the Sheriff's ranch and orders the gunman to surrender. Marsh grabs June for a shield and forces Cisco to drop his guns. Moving fast, Cisco kicks a chair at the outlaw, causing him to drop his gun. Both men scramble for the pistol but Marsh reaches it first. The desperate killer trains the weapon on the helpless girl...his finger tightens on the trigger...and fearless Cisco springs at him in a desperate attempt to prevent another killing!