In 1890, courier Frank Hopkins (Viggo Mortenson) and his dappled mustang Hidalgo were the undefeated champions of endurance riding competitions, races of hundreds, even thousands of miles. After Hopkins delivers a dispatch that leads to the massacre of Native Americans at Wounded Knee, he starts drinking, stops racing, and gets a job re-enacting cowboy and Indian battles in the Buffalo Bill show. Then he is challenged to compete in the world's oldest endurance race, a 3000 mile race across the Arabian desert. Also entering the competition is a horse owned by a powerful Shiekh (Omar Sharif), for whom winning is a matter of pride, and one owned by a titled Englishwoman (Louise Lombard), for whom it is a matter of money. A win would give her access to the finest thoroughbred Arabians for breeding. Hopkins and Hidalgo face treacherous conditions and even more treacherous competitors. A sandstorm, locusts, quicksand, and a detour to rescue a kidnapped princess provide many opportunities for swashbuckling action and spectacular cinematography.