On their way back to Fort Kirk from patrol duty, Lt. Billings and Sgt. Clarke are informed that they must deliver a treaty to the nearby trading post, where it will be picked up by a waiting lieutenant named Kirby. The treaty, which contains terms of peace that are satisfactory to both the Indians and the U.S. government, must be delivered to Chief Gray Cloud within nine days, or there will be war. The men, particularly Trooper Perkins, whose wife has just had a baby, are unhappy, and when they reach the trading post, they are dismayed to learn that Kirby has not arrived. Unknown to Billings and his men, Kirby and his men have been killed by Gray Cloud's son Taslik, an embittered warrior who believes the treaty will further weaken his people. When Taslik arrives at the post, Billings asks him to guide the troop to Gray Cloud's village. That night, as the soldiers listen to Trooper Charnofsky's stories about life in Poland, Taslik applies war paint and glares at them. When one of the men suspiciously inquires about the war paint, Taslik asks, "Do you not wear war clothes?" After a day's ride through desert terrain, heavy boulders destroy all but one of the soldiers' water barrels, and the next day, Billings is horrified to learn that the remaining barrel has sprung a leak. Taslik leads them to a spring, but it is dry. While the men sleep, Taslik steals away and receives water from his sister Wanima, who has been secretly accompanying the party and helping her brother to sabotage the water supply. Several mishaps later, Billings begins to suspect Taslik, and when all the horses are set loose, he finally confronts the brave. Taslik states that although his father considers white men honorable, he is certain the treaty will be broken. Determined to deliver the treaty, Billings order the men to continue, but it soon becomes apparent that Taslik has been leading them in circles. Exasperated and thirsty, a trooper named Tolson kills Taslik. Because the men are weak from thirst, Billings decides to send one man, Clancy, ahead to the village, but Wanima follows and shoots him. Before Clancy dies, he wounds her, however, and the detachment later stumbles onto the two fallen bodies. The soldiers want to kill Wanima, but Billings opts to take her along as proof that they want peace. Wanima leads the men not to water, but to a deserted gold mine. Grady, one of the soldiers, tries to kill Wanima, and when Billings defends her, Tolson shoots him in the arm. Realizing that Billings is sincere in his desire for peace, Wanima takes the party to a spring, thereby postponing a mutiny. That night, Tolson and two others decide to kill the loyal members of the troop so that they may plunder the gold mine. Clarke sends Billings and Wanima on to the village while he fends off the mutineers, but after the stabbing and shooting are over, only Tolson remains alive. As Billings and Wanima approach Gray Cloud's village, the soldier attacks them. A brutal fight ensues, but in the end, Billings stabs Tolson. Exhausted, Wanima and the lieutenant slowly enter the village together.