Mike Bates wants to build a railroad through a narrow area that can only accommodate one railroad, before his competitor Kathy Dale can manage to get hers through. If Bates gets his way, he will use the freight prices to drive the silver mines out of business and take them for a song. Kathy hopes to keep the silver mines going and leave the rate for freight low. Mike Bates uses brutal tactics, which Arizona Ames thwarts with the aid of his young nephew, Spurs.