Fifteen-year-old Charley Thompson arrives in Portland, Oregon with his single father Ray, both of them eager for a fresh start after a series of hard knocks. While Ray descends into personal turmoil, Charley finds acceptance and camaraderie at a local racetrack where he lands a job caring for an aging Quarter Horse named Lean On Pete. The horse's owner Del Montgomery and his jockey Bonnie help Charley fill the void of his father's absence--until he discovers that Pete is bound for slaughter.