After storekeeper Henry Turner (Peter Brocco) discovers that there is a huge gold deposit under the town of Blue Valley, he and henchman Brink Fallon (Roy Barcroft) scheme to drive out the citizens and claim the fortune, but Marshal Rocky Lane (Allan Lane) arrives to thwart their scheme. Lane goes undercover as deputy to sheriff Nugget Clark (Eddy Waller) and uses science, flying fists and his trusty horse Black Jack to battle the outlaws.