Charming tale of mountaineer-trapper Murphy's first taste "big city" life with young, sweet Sandra Dee in tow. She flees her family, which tried to trade her for some of Murphy's beaver pelts, and tags along with the reluctant Murphy. They get into all manner of trouble in town, and Murphy has to shoot the sheriff to rescue Dee from her job as a dancehall girl.

Upon completing their annual fur-trapping expedition, Lije Hawks, his wife Kiri and nephew Yancy travel homeward through the mountains of Wyoming. Lije is at first pleased to come upon a group of neighbors, but grows angry when he learns that they are giving up the difficult life of fur trading in favor of farming in California. Although Lije disparages farming and extols the freedom of the trapper's life, at their campsite that night he gives Yancy permission to farm, if he wants to earn enough money to marry. Aghast at the thought of leaving his family, Yancy gratifies Lije by vowing to pursue only a woman who also loves their lifestyle. Soon after, Lije is attacked by a bear. Yancy and Kiri fear for his life, but by morning he is as feisty as ever and instructs Yancy to trade the furs for supplies at Ogilvie's Trading Post. When Yancy arrives there, however, he discovers that the local Indians, inflamed by bootleg liquor, have accidentally set fire to the post, and Ogilvie is in the process of beating up Ben Stocker, the vagabond who sold the liquor to them. Yancy rescues Stocker but is chagrined to learn that the nearest trade area is in Casper, a two-day ride. As he prepares to camp for the night, Stocker, a con man with eight filthy children, eyes the furs and greedily offers to trade them for his eldest daughter Rosalie. Disgusted, Yancy chases Stocker off, but as he has guessed, during the night the drifter attempts to rob him. Although Yancy succeeds in scaring him away, in the morning he awakens to find Rosalie beside him. She explains that she has fled her father, and even though Yancy does not want the burden of caring for her, her wordless appeal persuades him to take her along to Casper. They reach the city, the largest either has ever seen, during the annual Independence Day celebration. The couple's provincial clothing elicits jeers from the locals, especially rowdy ranchhand Chip, who picks a fight with Yancy. After Yancy easily overpowers him, Chip aims a gun at him, but is stopped by Sheriff Paul Bartel, the owner of the town dance hall. Eager to leave, Yancy brings his furs to the general store, where proprietor Mrs. Forbes insists that her husband Cecil forgo the revelries outside in order to bilk Yancy of as much money as possible. Dance hall girl Marcy Howard enters the store, and an entranced Yancy, not comprehending that her job is akin to prostitution, decides to stay in Casper to woo her. He buys new clothes for himself and Rosalie, and after they change, she is thrilled at his transformation but he still fails to note her beauty. Dance hall manager Ma Ransome, tipped off by Paul, then arrives to offer Rosalie a position. The innocent Yancy turns Rosalie over to Ma and leaves for the fair, where Rosalie finds him and begs him to protect her from her new position. After insisting that he is not responsible for her, Yancy causes a commotion by fighting with a barker who swindles $100 from him. Paul, at the fair with Marcy, once again breaks up the fight, after which Yancy eagerly leaves Rosalie in Paul's care and approaches Marcy. She, however, is angry to see Paul leave with Rosalie, and spurns Yancy in favor of drinking with Chip, who abandons her when she passes out on the outskirts of the fairgrounds. Yancy tends to Marcy all day, and when she revives, she is charmed by his tenderness and gallantry. The sun sets, signaling the start of the dance. Yancy manages to convince Marcy to join him on the dance floor, but as she has expected, the townspeople are outraged to see her there. When Chip starts a fight with Yancy over Marcy, the locals protest her presence, and Yancy finally realizes Marcy's profession. He is further disheartened when he proposes to her and discovers that she prefers to stay in Casper rather than leave with him. Suddenly aware that he has abandoned Rosalie to the same fate, Yancy rushes to the dance hall, heedless of Cecil's warning that Paul will not accept any interference. Meanwhile, Paul has instructed Ma to outfit Rosalie as a prostitute, and is delighted with the result. At a private dinner, he tries to persuade the young girl that he will protect her and hopes that she will renew his faith in women, whom he considers coldblooded. Yancy appears downstairs, but, upon being thrown out by Paul's guards, calls to Paul from the street. Paul hides in the shadows on the balcony and urges Yancy to give up, drawing his gun as he speaks. Just as Paul shoots, Yancy leaps to the side and fires back, wounding Paul. The sheriff falls to the street, where he apologizes to Rosalie, then dies. Days later, Yancy prepares to leave Casper. The Forbeses, who have taken in Rosalie, ask him to stay to finish cleaning up the town, but Yancy yearns to return to Lije and Kiri. When Rosalie follows him to his horse, Yancy dismisses her roughly, but cannot resist her intent gaze. Soon after, the Hawks family, which now includes Rosalie, happily sets out again toward home.