Ken McLaughlin's
mustang mare Flicka gives birth to an all-white colt that, unknown to Ken's dad, Rob, was actually sired by a neighboring rancher's
thoroughbred racehorse, Appalachia, rather than Rob's own
stallion, Banner. The colt, nicknamed "Goblin", proves to be difficult, but Ken trains him to race. Ken's mother, Nell, officially names the colt Thunderhead after the billowing white clouds she sees overhead. Thunderhead is entered into his first race with Ken as the jockey, but he suffers an injury, ending his racing career. Meanwhile, the Albino, a wild mustang stallion that has been raiding local ranchers' herds for years, steals Rob's best mares and kills Banner, putting the family near bankruptcy. Although Banner was Flicka's sire, the Albino is Flicka's grandsire and Thunderhead's great-grand-sire. Rob, Ken, and the ranch hands search for the mares, but during the night, Thunderhead gets loose and runs off. Tracking Thunderhead on foot to a secluded valley, Ken discovers the Albino's herd, including his father's horses. The Albino attacks Ken, but Thunderhead fights and kills the Albino, saving Ken's life. Rob and the others arrive as Thunderhead rounds up the Albino's herd, heading them to the McLaughlin ranch. But once there, Thunderhead is uneasy. Rob tells Ken that Thunderhead is a king now and wants to roam his realm. Ken removes Thunderhead's halter, freeing him. ==Cast==