Buffalo Bill Cody and his sidekick Gabby ride to the New Mexico territory to help Colonel Joe Calhoun of the U.S. Cavalry conduct a land survey. The military's efforts have been hampered by a series of Indian raids led by the Comanche medicine man Akuna and by the opposition of Don Regas, the largest land holder in the territory. Unknown to Don Regas, his ranch foreman, Emilio Montez, is in league with Akuna, his half brother, to wrest control of a secret gold mine located on the Regas land. Colonel Calhoun has asked Bill and Gabby to look after his tenderfoot son Jerry, who is coming from the East to complete the survey, and Bill, who is attracted to the don's granddaughter Tonia, convinces the girl to persuade her grandfather to cooperate with Jerry. Montez has other plans for Jerry, however, and after luring the boy into losing all his money gambling, Montez demands that he falsify the survey to exclude the northern section of the Regas land, the portion on which the mine is allegedly located. When Don Regas learns that he has been denied part of his land grant, he angrily denounces the survey and boards the east-bound stage to challenge the document in Washington. Montez informs Jerry that they must eliminate Don Regas, and when Jerry threatens to tell his father, Montez stabs him, takes him prisoner and orders Akuna to ambush the stage. Meanwhile, Bill, suspicious of the survey, discovers that Montez has filed a claim on the land and, anticipating trouble, rides after the stage. Arriving just after the Indians have attacked, Bill and Gabby drive the marauders away and take the injured Don Regas to his ranch. That night, Montez sneaks into the ranch house to search for the land grant documents, and Gabby and Bill follow him back to Akuna's camp. There, Jerry warns them of a planned attack on the hacienda, and Gabby rides for the cavalry as Bill and Jerry ride for the ranch. Gabby and the reinforcements arrive just in time to rout the Indians, and after Jerry admits that he made a mistake in the survey, Don Regas is accorded his entire land grant.