In 1847, while leading a wagon train of settlers traveling from Missouri to Portland, Oregon, Glyn McLyntock saves a suspected horse thief, Emerson Cole, from a lynch mob. Although Glyn recognizes Cole as a former Missouri border raider, the two become friends and Cole joins the wagon train. That night, six Shoshone Indians attack the camp and shoot a settler, Laura Baile, in the shoulder with an arrow. Cole follows Glyn as he bravely attacks the Indians and, after saving Glyn from one, hears Glyn's gunshots signal the death of the five others. The next day, Glyn notes with disappointment that Laura is attracted to Cole, and reveals to the younger man that he is running away from his younger self. In Portland, the settlers receive a warm welcome from saloon owner Don Grundy and local steamboat owner Tom Hendricks. As Laura is tended to by doctor and riverboat captain Mello, her father, Jeremy, spends all the settlers' money on supplies Hendricks is to deliver in a few months. Handsome gambler Trey Wilson arrives in town that night and spurns the attentions of Laura's younger sister Marjie, in order to play poker with Cole and Grundy. During their game, Grundy recognizes Cole as a former raider, and when Trey accuses the saloon owner of cheating, Cole shoots Grundy. The next day, everyone except Cole, who is staying in town, and Laura, who needs to recuperate for another month, boards the steamboat and heads to the settlement. Jeremy confides to Glyn that he does not like Cole because he believes that once a man has gone bad, he cannot be reformed. Over the next months, Jeremy presides over the building of the settlement's farms, homes, school and church. By mid-October, however, neither Laura nor the supplies have arrived, and the settlers are in danger of starving once winter sets in. Glyn and Jeremy travel to Portland to retrieve the supplies, only to discover that the town has been transformed by an influx of gold miners, and that greedy Hendricks is holding their goods, now worth five times their former value. Glyn hires out-of-work miners and instructs them to load their supplies onto the steamboat, then finds Hendricks in the new gambling hall. There, Cole works as Hendricks' pit boss, with Laura by his side. Glyn advises Laura to inform her father of her decision to stay in Portland, then confronts Hendricks, who refuses to give up the supplies and instead shoots at Glyn. Cole and Trey leap to Glyn's defense, and the three are forced to flee to the steamboat, where they convince Captain Mello to help them, along with Jeremy, Laura and the miners, to escape. With Hendricks and his men on their trail, Glyn convinces the miners to help them bring the supplies over the mountain. That night, Glyn positions them in the hills and so is able to kill off Hendricks and his men. As they begin the perilous journey over the mountain, they meet hungry miners, who have also been tricked out of their food by Hendricks. Cole and Red want to accept the miners' offer of $100,000 for the supplies, but Jeremy refuses to sell. Soon after, the miners revolt against Glyn, and although Cole saves Glyn, Jeremy's leg is injured. The next day, Cole, who cannot resist the other miners' money, beats up Glyn, leaves him horseless and abducts Jeremy, Laura and the supplies. As Glyn tenaciously tracks the wagons on foot, Cole grows more depraved. Laura frees a horse for Glyn to find, and two hours outside of the mining camp, Glyn attacks. Desperate, Cole beats Jeremy and then shoots at Trey when the gambler defends the older man. Cole takes off for the mining camp to round up help, and before Glyn, Laura, Trey and Jeremy can get the supplies back to the settlers, Cole and his men appear. Trey and Jeremy shoot down the miners as Cole and Glyn fall into the river, locked in combat. Glyn finally knocks out Cole, and the criminal drowns. When Glyn staggers out of the river, Jeremy sees the scars around his neck and, realizing that his friend is also a former border raider, admits that he was wrong about the ability of men to reform. Soon, the settlers joyfully welcome the group back, and as Trey approaches Marjie, Jeremy proudly watches Laura joining Glyn in his wagon.