Penny Chenery Tweedy inherits her ailing father's Virginia horse farm despite her limited knowledge of horse racing. Determined to save the farm, she enlists the help of veteran trainer Lucien Laurin. Together, they pin their hopes on an unproven yet promising colt named Secretariat. Faced with financial difficulties and skepticism from the racing community, Penny remains steadfast in her belief in the horse's potential. Her journey is marked by challenges, including family opposition and the intense pressure to succeed.

As Secretariat starts to race, he quickly attracts attention for his extraordinary speed and stamina. Penny, alongside Lucien and a dedicated team, nurtures Secretariat's talents, preparing him for the grueling path to the Triple Crown. Secretariat's victories and the pursuit of greatness drive the story forward, showcasing the deep bond between Penny and the horse, as well as the support of those who believe in them.