Despite her lack of experience, housewife and mother Penny Chenery (Diane Lane) agrees to take over management of the family Thoroughbred farm after her father (Scott Glenn) becomes ill. Successfully navigating her way through the male-dominated world of horse racing, Chenery, together with veteran trainer Lucien Laurin (John Malkovich), fosters a gifted colt that ultimately crosses the finish line into history as the Triple Crown winner in 1973.