Plot
During the Apache Wars of the late 19th Century, former soldier Merrick Beckford is tasked by the US Army to deliver a shipment of essential medical supplies to San Carlos, Arizona through hostile Apache territory. Beckford accepts the job and sets out alone with two mules and a wagon.
Four days into his journey, Beckford encounters the survivors of a traveling party raided by Apache warriors. The five-member party consists of frontier settlers Valerie Butler and her husband Jeff, and their three traveling companions: gunhand "Mule" Charlie McKee, his subordinate Edmund, and his son Billy. Jeff was gut-shot in the attack and is in critical condition. After a tense introduction, Beckford warily allows the group to travel with him in the medicine wagon.
McKee's group wishes to quickly travel back north to the nearest settlement, leaving Jeff to die lest he slow them down, for fear that the Apaches will return to finish them off. To Valerie's relief, Beckford refuses to leave the injured man behind. Beckford also refuses to alter his southward course to San Carlos, which will take them to a nearby watering hole where the group can recuperate. Upon reaching the oasis, Beckford removes the bullet from Jeff's wound. Tensions continue to rise between Beckford and the other three men, especially Edmund, who openly resents Beckford's authority. The trio become more insistent that the group travel north instead of south.
During negotiations, the group is interrupted when Billy senses the approach of an Apache scout. He and Beckford go to investigate. Beckford recognizes the scout and addresses him as a friend, but before they can begin to talk, Billy shoots the Apache dead where he stands. Furious, Beckford demands the other men bury the scout's body in hope of delaying the other Apaches from discovering what happened. The earlier negotiations escalate to threats of violent mutiny from Edmund, but Beckford is unmoved and McKee talks Edmund down.
While the other men are burying the body, Beckford visits the grave of his brother, a notorious Confederate outlaw who was brutally murdered two years prior while awaiting a pardon at the watering hole. He suspects that McKee and his men are responsible for his brother's death, but is not certain enough to act on this suspicion. Over dinner, McKee reveals that he and his men are traveling with a great deal of money. He offers Beckford $1000 to change course. When he is again refused, McKee finally drops his courteous attitude and openly declares his intent to violently take Beckford's wagon and mules.
During the night, the trio attack Beckford as he keeps watch. Beckford knocks Edmund unconscious and fatally shoots Billy. The next day, Jeff has recovered enough to speak and walk. He confides in Beckford that he is terrified to travel through the long stretch of Apache territory and begs him to turn northward, offering to divorce Valerie so that Beckford can have her. Disgusted at Jeff's cowardice, Beckford refuses.
As he is preparing for the group's departure, Beckford discovers that the Apaches have found the dead scout and are preparing to attack. The group leaves in haste but are quickly caught by the Apache war party, taken prisoner, and delivered to Chief Victorio. Seeing no point in further deception, McKee and Edmund reveal to Beckford that they are outlaws who robbed a bank in San Carlos, and that they are indeed the ones who killed his brother.
Victorio tortures the men, promising that if any one of them can withstand the pain without begging for mercy, he will let the entire group go free. Jeff, Edmund, and McKee fail to endure, but as Victorio is about to torture Beckford, he recognizes him as the victim of an unsanctioned renegade Apache attack some years prior. The attack had claimed the life of Beckford's wife and left him heavily scarred, and in recompense Beckford had been declared a non-combatant to be left alone by the Apache tribe. Victorio releases Beckford and promises him safe passage to San Carlos, leaving him to deal with the rest of the group as he sees fit.
As Beckford prepares to continue his journey south with Valerie and Jeff, Edmund and McKee break free of their bonds and incapacitate him, but Beckford is saved by Jeff's intervention. In the ensuing brawl, Jeff and Edmund are killed and McKee is blinded. Beckford offers McKee the choice of being taken to San Carlos to stand trial and be hanged, or being executed on the spot. McKee chooses execution and Beckford obliges. Beckford and Valerie return to the watering hole, bury the three dead men, and continue their journey together.
