Rick Largo, a restless man on the run after a bank robbery, convinces his partner Frank Banner to shoot John Carter (aka Hamilton), so they can split the loot two ways. Johnny, however, only pretends to be dead. He trudges forty miles with his saddle to Christian Flats, buys the last horse in town, and throws down a challenge to his brother in a tense shoot-out. Frank misses, and Johnny spares his life, telling him to get out of town. A fresh confrontation soon follows when Johnny faces Largo in a second duel; Largo is killed. With vengeance satisfied, Johnny sets his sights on Laramie, Wyoming.
Meanwhile, saloon singer Amy Clarke also aims for Laramie. She wants to recover $27,700 stolen from her in Abilene by a crooked agent and former sweetheart who is now heading for Canada. The Mile High stage to Laramie is full, but Amy bribes the clerk with one of her scented garters to secure a seat. When the overdue stage finally arrives, the driver and horses are laden with Cheyenne arrows, and all the passengers are dead. Undeterred, Amy insists on riding anyway and convinces Johnny to drive the coach, attaching his newly purchased horse to the rig.
Amy’s French maid, Giselle, refuses to accompany her, but four other passengers join: the flamboyant Senator Blakeley, the bank clerk Carter Hamilton who is desperate to track down the outlaw to clear his name, Mark Chester, a Pennsylvania gold speculator, and Minstrel, Amy’s accompanist and protector. En route, they discover Frank’s corpse in a waterhole pierced with Cheyenne arrows. It’s then that Johnny reveals Frank is his kid brother.
A wheel breaks, the stage wrecks, and the horses bolt. The travelers take refuge in a dry creek gully, but Cheyenne attacks persist, and Chester is killed along with his bag of fool’s gold. A full-scale rifle battle erupts as the Indians wait in the rocks above, while thirst tightens its grip on the party.
Amy berates Blakeley for his pacifist stance amid the onslaught, though he continues to defend his beliefs. Hamilton and Johnny decide to steal one of the Indians’ horses to seek help; Hamilton is wounded, and Johnny shoots the attacking Indian, saving him, but the horses slip away. When they return, Blakeley makes a move on Amy, only to be rebuffed by her, who calls him “father,” fueling Johnny’s jealousy. The drought intensifies, and Minstrel, seeing a mirage, insists on approaching it—while Hamilton, delirious, points a gun at Johnny, convinced the lie about water was true. Minstrel is shot by the Indians, and Amy laments the tragedy, questioning whether words alone can bridge the divide.
Hamilton grows sicker, and Johnny undertakes a dangerous rescue mission to fetch a canteen the Indians planted as a lure. The canteen turns out dry, and Johnny taunts the Indians. Then rain swells the gully with water, and Amy arrives with a drink for Hamilton only to find him dead. An Indian survivor, weaponless for now, clashes with Johnny; the fight ends with Johnny sparing the man’s life and urging him to return to his people and tell them a white man had spared him. The Indian understands and speaks halting English.
Johnny vows to honor Hamilton’s memory by clearing his name and returning the money to the bank. Amy, who has grown wary of her former sweetheart, embraces Johnny as the Indians circle back. The spared Indian returns bearing two horses as a gift, saying, “That is part of the gift.” He will walk back to his people. The pair mournfully notes that Blakeley would not live to witness this final act of friendship.
