The film is based on "Secretariat," the 1973 Triple Crown-winning racehorse and its owner, Penny Chenery (Diane Lane).
Chenery was a mother and housewife who knew little about horses when she was pressed to take over her ailing father's horse farm in Virginia. Though Secretariat came along and began to take shape as a potential champion, Chenery was pressured to sell the farm after her father died and she was hit with a multimillion-dollar inheritance tax.
She saved both the farm and the horse, and watched as Secretariat became the first thoroughbred to win the Triple Crown in 25 years, taking the Kentucky Derby, Preakness and Belmont Stakes in dominating fashion. Chenery became known as the "first lady of racing."