In 1890, Frank T. Hopkins and his mustang, Hidalgo, are heralded as the world's greatest long-distance racing team, having gained fame in the United States for winning numerous endurance races. Despite the acclaim, Hopkins battles personal demons tied to his identity and the massacre at Wounded Knee, which he survived but left him disillusioned. His claim to fame catches the attention of a wealthy Sheikh who invites him to the Middle East to participate in the Ocean of Fire, a treacherous 3,000-mile survival race across the Arabian Desert. It is a challenge that pits the finest Arabian horses against an outsider and his mustang, a breed considered inferior by the Arab competitors.

Upon arrival, Hopkins and Hidalgo are met with scorn and skepticism from the other racers, who doubt their endurance and the rider's claim to be a cowboy. The race not only tests their physical limits through deadly sands, fierce storms, and scarce water sources but also confronts them with cultural clashes and treachery from competitors determined to uphold the race's exclusivity to purebred Arabian horses. As they journey deeper into the desert, Hopkins must navigate not only the physical adversities but also the moral dilemmas and personal conflicts that arise, challenging both his identity and the bond with his horse, pushing them to the brink in a quest for survival and redemption.