In the 1890s, David Palmer, a chemist in Chicago, returns to his home town of Oxford, Indiana, to marry schoolteacher Ruth Treadwell. David's father Dan and his aunt Netty greet him at the family's farm, where Dan breeds racehorses. Dan's horse trainer, Ben Lathrop, has a tomboy daughter Cissy, who is still in high school but has developed a crush on David. Dan has hoped that David and Ruth would live with him on the farm after they marry, but David announces that he has taken a new job in Indianapolis. Ruth, a social climber, is disappointed that they will not be living in Chicago, but they buy a large estate in Indianapolis and settle there. David returns to Oxford for track debut of Zelica, his father's new horse, but tragedy strikes when Voodoo, the groom, hooks Zelica up to a damaged sulky and the horse suffers career-ending injuries. However, as Zelica exhibited great stamina, Dan decides to breed her with Joe Patchen, a great stud horse in Illinois. A colt, Dan Patch, is born of the mating and develops into a potential champion. When Dan experiences a recurrence of a heart problem, Ben and Cissy decide to alert David and travel to his grand estate, replete with butler and maid, where they are treated badly by Ruth, who has become a socialite and has no interest in horses. After Ben tells David that Dan Patch has run a record quarter-mile in training, he and Cissy leave. Later, David receives a telegram from Aunt Netty informing him that his father is sick and he leaves immediately for Oxford. As his father dies, while looking at Dan Patch outside his window, David promises that he will take over the horse's development. When David decides to build a training track at the farm, Ruth is very critical of the cost, and David realizes that he is trapped in a loveless marriage. Dan Patch's first public appearance at the Boswell County Fair results in a win. After several more wins in Indiana, David and Ben decide that the horse is ready for the grand circuit-- Detroit, Cleveland and Columbus--where he triumphs. At Lexington, Kentucky, Ben, who has been driving the horse, has an attack of sciatica, and he and Cissy persuade David to take over. However, as all the other drivers have withdrawn their entries, knowing that their horses cannot beat Dan, David agrees to run Dan in an exhibition mile against time, and against the two minutes, one and one-quarter seconds of his sire, Joe Patchen. Dan breaks the record by running the mile in one minute, fifty-nine and three-quarter seconds. After the race, David receives a telegram from Ruth summoning him back to Indianapolis, where she tells him that an important chemical contract has been canceled and expresses great concern about the security of their lavish life-style. She insists that he sell Dan and the farm. When David goes to the farm to explain the situation to Ben and Cissy, he discovers that she is being courted by a young driver, Bud Ransome. As Cissy and David care for a foaling mare, a fire breaks out in the stable, but they are able to extinguish it and save the horses. Later, David returns to Ruth, and informs her that he intends to keep the farm and sell their estate. Ruth, ever the social climber, refuses to contemplate living on the farm, and they decide to go their separate ways. David surrenders everything, except the farm, to her. Cissy is thrilled when David returns and he begins to realize the depth of her affection for him. They both agree to sell Dan Patch for $60,000 and, over the next four years, the horse tours the country in a private rail car, racing at state fairs and attempting to beat his own record. The horse's name is used to promote cigars, sarsaparilla, playing cards and sacks of feed. Dan eventually reduces his record time to one minute, fifty-six seconds and in September 1906, runs his last race before retiring at the Minneapolis State Fair. Dan and Cissy have married and bring their young daughter and Ben to see Dan run his final race. To the great delight of the crowd, Dan beats his own record by a second.