Despite knowing nothing about horse racing, stay-at-home mum Penny Chenery agrees to take over the Meadow Stables in Virginia after her father falls ill. With the help of veteran trainer Lucien Laurin, Chenery manages to overcome the odds by navigating her way through an aggressive, male-dominated business and ultimately producing the champion racehorse, Secretariat, who becomes the first Triple Crown winner for 25 years in 1973.