When Jim Craig and his father Henry are engaged in a discussion about their finances, an unexpected event occurs: a herd of wild horses known as the Brumby mob gallops by. Henry, driven by a desire to eliminate the black stallion leader, is persuaded by Jim to instead capture and sell the horses. As the two of them construct a yard designed to trap the mob, chaos ensues when the herd makes a sudden reappearance, trampling through their area. In the ensuing turmoil, tragedy strikes when the Craigs' horse bolts with the mob, resulting in Henry's accidental death.
Before Jim can inherit the family station, he is confronted by a group of rugged mountain men who insist that he must first earn this right by seeking work in the lowlands. With the help of an old friend of his father's, Spur, a one-legged miner, Jim receives a horse to embark on his journey. He subsequently secures a job at a station owned by Harrison, Spur's brother, thanks to a recommendation from Andrew Patterson—a character inspired by the renowned poet A.B. (Banjo) Patterson.
While this unfolds, Clancy makes an appearance at Spur’s mine, where he and Spur reminisce about their pasts and contemplate their futures. Clancy then heads to Harrison's station to oversee a cattle muster. During dinner, a tense conversation arises, wherein Harrison dismisses Spur, stating, "he has no brother."
As Harrison organizes a round-up of his cattle, Jim finds himself sidelined. In his absence, Harrison’s daughter, Jessica, approaches him and requests help to break in a valuable colt. However, the Brumby mob reappears, and Jim's attempts to chase after the prized horse fail. When Harrison returns, he orders Jim to fetch back twenty stray cattle. Soon after, Harrison learns of Jim's unauthorized actions and informs Jessica that not only will Jim be dismissed, but she too will be sent away to a women’s college. Driven by emotion, Jessica rides off into the treacherous mountains, where she becomes trapped in a fierce storm.
In a stroke of fortune, Spur discovers a rich gold deposit. While Jim valiantly searches for Jessica’s horse and ultimately rescues her, she reveals her impending dismissal. Surprisingly, she encounters Spur, her long-lost uncle, of whom she was previously unaware. The emotional encounter is complicated when Spur mistakenly associates Jessica with her deceased mother, refusing to share details from his past.
Later, upon returning, Jessica learns about the romantic history between Spur and her late mother, Matilda. Spur had set off to find gold while Harrison took a gamble on a horse race, which fortune favored, enabling him to marry Matilda, who tragically died during childbirth. Although Harrison appreciates Jim's courage in saving Jessica, tension mounts when Jim confesses his feelings for her.
As Jim prepares to depart, a prized colt is inadvertently let loose by a farmhand named Curly, aiming to frame Jim for the incident. While camping under the stars, Spur reveals that Jim will inherit his father’s stake in the mine. Clancy joins the two and brings news about the runaway colt, yet Jim adamantly declines to pursue it.
Meanwhile, the allure of a £100 reward from Harrison for capturing the colt attracts various riders and opportunists from neighboring stations. Eventually, Clancy joins Jim in the search, leading to a turn of events as Harrison finally grants Jim permission to join the hunt. The chase unfolds with numerous accidents as riders struggle to corral the Brumby mob. Just when the others abandon the pursuit at a perilous descent, Jim bravely pushes forward, successfully returning the horses to Harrison’s property.
In a gesture of gratitude, Harrison offers Jim the reward, which he humbly declines. With his name cleared, Jim expresses a desire to one day return, not just for the horses, but to reclaim "anything else that's mine," as he glances meaningfully at Jessica. He rides back to the mountainous terrain, knowing he has rightfully earned his place there.
