In this above-average western, a villainous land grabber attempts to force horse ranchers to sell their ranches so he can become king of the horse market. One stubborn rancher refuses to relent and his killed. His two surviving sisters then continue the fight. They are soon assisted by a passing drifter who ends up falling for one of them. In the end a gunfight between the good and bad guys ensues.

Inasmuch as western star Charles Starrett gained screen fame as the Robin Hood-like "Durango Kid", it stands to reason that Starrett would head the cast of Robin Hood of the Range. The star plays Steve Marlowe, the foster son of railroad manager Henry Marlowe (Kenneth McDonald). When it becomes apparent that the railroad is using underhanded methods to drive local homesteaders off their land, Steve adopts the guise of "The Vulcan", a legendary champion of justice.

The Three Mesquiteers convince a group of settlers to exchange their present property for some which, unbeknownst to our goodguys, is going to be worthless. They are captured before they can warn the ranchers.

In his starring debut, Roy gets elected to Congress in order to bring water to the ranchers in his district. In Washington, he learns he needs the backing of a key congressman and gets that man to go west for an inspection trip. When the congressman is initially unimpressed, Roy gets the inspection party stranded without water to show the true conditions.