The Conquering Horde (1931)

Not long after the Civil War, Texas cattle ranchers realize they have a problem--the Union Pacific railroad is bypassing their state and make it near impossible to get their cattle to market. Many ranchers are being forced to sell their land, and crooked state treasure Marvin Fletcher buys up the land at pennies on the dollar. However, Laguna del Sol Ranch owner Taisie Lockhart and her ranch hands are holding out. Cowboy Dan McMasters returns to the ranch and tries to rekindle his romance with Taisie, but she rejects him because he fought for the North during the war. But what she doesn't know is that Dan is on an undercover mission from the President to investigate Fletcher, and in order to do that he has to pretend to be sympathetic to Fletcher and goes to work for him, angering Taisie even more. Complications ensue.