When logging partners Jim Hadley and Monty Welker arrive in the Northwest frontier town of Deep Well, the townspeople greet them with disdain, including general store owner Peterson, who reluctantly sells Jim provisions, and the livery stableman, who refuses to rent him horses. The sole person to befriend Jim is teenager Bert Harvey, who offers him a ride to the Riley ranch, where he works, suggesting that he might be able to rent horses there. When they reach the ranch, however, owner Laura Riley curtly tells Jim that the logging will cause their topsoil to be washed away, destroying their range for the cattle. After Jim claims that the watershed is not his problem, Laura orders him off her land. With only nine weeks to fill a government lumber contract for the railroads, Jim and his men begin cutting trees. One day Bert arrives at the work site and, awed by the fearless lumberjacks scaling gigantic trees, tells Jim he wants to be a lumberjack to pay back Laura and Aunt Sarah for taking him in after his father died. Meanwhile, Laura gathers the ranchers together to formulate a plan to thwart the loggers while they are diverted by the Saturday night dance. On Saturday night, the drunken lumberjacks head for the dance hall, and when the townsmen prevent them from entering, a brawl ensues. Hearing several explosions, everyone rushes to the lumberjack camp, where an avalanche of rocks, caused by the explosions set by the ranchers, now blocks the logging road. The townsmen and ranchers laugh at how easily they have thwarted the loggers. Because the only other existing road to the logging area runs through Laura's ranch, Jim decides to build a new road, but the difficulty of the task disgruntles his men, including Monty, who is losing faith in Jim. Later in town, Jim ignores the townspeople's mocking jeers and, determined to "win," tries to buy Laura's ranch and accuses her foreman, Clay Bell, of blowing up the mountain. After Laura refuses Jim's offer, she takes him to nearby Green Meadow to explain Clay's extreme action. Green Meadows was once a thriving town where Clay was raised, but he never got a chance to be a rancher like his father because logging destroyed the watershed and the now deserted town. Laura tells Jim that he cannot hate them for fighting for their lives, but Jim, far from hating her, takes Laura in his arms to kiss her. Later, under pressure from Monty, Jim applies for a temporary easement which will allow him passage through Laura’s ranch; however, when Jim and his men arrive at the ranch gate, Clay orders the surrounding trees cut, blocking Jim's path. When the sheriff shows Laura the legal documents, she asks where permission to log is written in the document, forcing Jim and his men to await the clearing of the road. Later in town, the sheriff asks Jim to try to understand the damage that logging will cause to the town and to give him time to speak with Laura. After Jim gives him until noon the next day, the sheriff comments, "For a lumberjack, you sure don't know much about roots." Meanwhile, Bert tells his girl friend Jane, Peterson’s daughter, that he intends to become a lumberjack, prompting the young woman to slam the door on him. Having witnessed the argument, Jim suggests to Bert that he remain in Deep Well to help the women who need him. When he returns to camp, Jim discovers that Monty and a few men have taken off with the dynamite and plan to stop Laura. Meanwhile, Monty is preparing the dynamite near the Riley ranch gate when Bert, hearing a noise, decides to investigate. Desperate to break through the roadblock, Monty beats Bert unconscious then flees into the hills with his men to set off the explosives. Jim approaches just after the explosion and finds Bert badly injured. After Jim carries the boy to the ranch house, Aunt Sarah caustically states, "I hope your timber is worth it." Jim apologizes to Laura and later confronts Monty, warning him that if Bert dies the town will lynch them. When Monty refuses to stop his violent tactics, Jim and Monty fight. Throwing the last punch, Jim then crawls away and orders Monty to leave. Deciding to leave town the next day, Jim goes to see the recovering Bert, and after advising him to become a ranchhand, wishes Laura farewell, telling her that he found something more important than timber in Deep Well. When Jim walks out Laura’s front door, Monty, Vince and several other men shoot at him. Laura throws him a loaded gun, which he uses to shoot Vince and wound Monty, while the others flee. An obsessed Monty races into the nearby forest and sets fire to the trees to prevent anyone else from taking the timber. As the flames quickly spread, Jim sends Laura to Deep Well to fetch the townsmen and his lumberjacks while he and Clay set dynamite around the edge of the fire, hoping to isolate the flames from the rest of the forest. Remembering Monty is trapped in the burning timber, Jim runs into the forest to find him, while Clay is forced to set off the explosives to stop the hillside fire. As the trees fall around them, Jim rescues the badly wounded Monty and carries him out to the fire's edge, where the lumberjacks and townspeople watch as Monty asks for forgiveness and dies. Later, as the train pulls out with the lumberjacks, the townspeople thank them for saving the watershed as Laura jumps on board with her bag to join Jim. When Jim teasingly warns her that she will not have a home and that he is the boss, Laura tells him she has given Aunt Sarah the ranch and gladly submits to his authority.