tells McNally that Tuscarora needs help; his father and other ranchers are having land stolen by a rich man named Ketcham, who had the previous sheriff killed and installed Hendricks in his place. McNally, Cordona, and Delaney go to Rio Lobo, where they find the people living in terror of Hendricks and his men. Tuscarora's girlfriend Maria hides them in her house, while her friend Amelita distracts Hendricks' men. Hendricks has Tuscarora arrested on trumped-up charges, so McNally's group goes to get help from Tuscarora's father, Old Man Philips. McNally, Cordona, and Philips sneak into Ketcham's ranch, and McNally discovers that Ketcham is really Union Sergeant Major Ike Gorman, the second traitor he was searching for. McNally attacks Gorman and forces him to sign the deeds back to their rightful owners. Taking Gorman hostage, they send Cordona ahead to find the United States Cavalry. Upon arrival in Rio Lobo, they discover that Hendricks has beaten Maria and disfigured Amelita's face with a knife for helping McNally. Amelita swears to McNally that she will kill Hendricks herself. The men force Hendricks' party out of the jail and hole up there with Tuscarora to await the Cavalry. However, Hendricks' men capture Cordona before he gets far, and offer to trade him for Gorman. During the prisoner exchange, Cordona manages to give his captors the slip. McNally tells Hendricks that Gorman is no longer of any use to the sheriff, since he signed back the deeds. Angered, Hendricks guns down his own boss, starting a firefight in which he and McNally are wounded. After a failed attempt to blow up the cantina McNally's allies are using as a base, Hendricks' men are outflanked by the rest of the townspeople, who have rallied to help. Hendricks' men abandon him. Hendricks tries to shoot at them, but he has been using his rifle as a crutch and, with its muzzle clogged with dust, it explodes in his face. As he stumbles to his horse, Amelita shoots him, thus fulfilling her promise to McNally. Cast John Wayne as Col. Cord McNally Jorge Rivero as Capt. Pierre "Frenchy" Cordona Jennifer O'Neill as Shasta Delaney Christopher Mitchum as Sgt. Tuscarora Phillips Jack Elam as Phillips Victor French as Sgt. Major Ike Gorman/"Ketcham" Susana Dosamantes as María Carmen Sherry Lansing as Amelita David Huddleston as Dr. Ivor Jones – Dentist Mike Henry as Rio Lobo Sheriff "Blue Tom" Hendricks