In 1867, during America's expansion into Indian territory, the small Arizona town of San Remo comes under siege by an Apache war party led by Charlie Wolf, a "half-breed," who is protesting the corrupt Indian agency in charge of administering aid to Apaches. Dan Craig, a gambler passing through San Remo, takes an interest in the dispute when he suspects that San Remo's Marshal Cassidy is in league with Kraemer, the double-dealing Indian agency head. During his stay in San Remo, Dan also becomes involved with Helen Dowling, a pretty young singer who is planning to leave San Remo for San Francisco to further her career. The siege, which has been deliberately instigated by hotel owner Crawford and his men, who are planning to use the unrest as their excuse to make a claim on the gold buried under the Indian reservation, is momentarily suspended when Wolf enters Crawford's hotel with his gun lowered, asking for the surrender of Kraemer. While the townspeople view the proceedings in disbelief, Dan and Wolf begin negotiations. The temporary truce is soon broken, however, when Crawford starts a gun battle with the Apaches. Despite the attack by Crawford, Wolf sees a trustworthy friend in Dan and knows that he is sincere in his efforts to avert further bloodshed. As smoke signals emanating from the reservation announce impending war, U.S. Cavalry troops under the command of Capt. Jackson arrive in San Remo. At the captain's request, Dan relays a message to the Apaches that the government is willing to dismiss Kraemer from the agency in exchange for peace. The Apaches accept the offer, but as Dan and Wolf ride back to San Remo, Dan is wounded in an ambush. Soon after Dan and Wolf arrive in San Remo, Wolf meets Helen for the first time and falls instantly in love with her. Kraemer is later replaced by Dan as the local agency representative, and Wolf is made his assistant. The first attempt by the Apaches to get supplies in San Remo with Dan as head of the agency ends in tragedy, however, when Crawford's men ambush the caravan, steal their goods and kill many Indians. Later, when Dan finds Wolf forcing his attentions on Helen, the two men quarrel, and Wolf leaves San Remo. Hoping to prevent the Apaches from retaliating for the ambush, Dan promises to return their stolen goods and bring the culprit to justice. The fragile truce is further strained when Wolf's sister Nah-Lin is found murdered. One of Crawford's men, Russell, is arrested for the Nah-Lin's murder, but, faced with certain death at the hands of the Apaches, he names Crawford as the real culprit. Shortly after the admission, Crawford kills Russell. Dan chases after Crawford, kills him and delivers his body to the Apaches. Satisfied with the death of Nah-Lin's killer and the source of corruption in San Remo, the Apaches call off the war party and Wolf and Dan patch up their differences. Wolf decides to return to the reservation to help enlighten his people about the white man's ways.