The heiress to a racing stable uncovers underhanded dealings.

After race horse Gay Fleet comes in last for the fourth time in a row, trainer Rick Grayton and jockey Manuel Morales discuss Rick's plan to keep the horse from winning so that he can buy it from its owner, New York actress Carol Maldon, for far less than it is worth. When Rick and Manny reach the next town on the gypsy racing circuit, they are surprised to find that Carol is a guest at their hotel. Carol, a racing novice, explains that she has come to take charge of the "stable" she inherited from her father, unaware that it consists of only one horse. Rick takes Carol to Ma Parkson's farm, where Gay Fleet is boarded, and they meet the glamorous Mercedes Bellway, who is immediately attracted to Rick. That night, Rick plies Carol with wine, reminisces about his long friendship with her late father and offers to buy Gay Fleet for $500. After sending the tipsy Carol to bed, Rick joins Mercedes in the hotel bar and is delighted to learn that she is from a wealthy family that owns a chain of stables. Meanwhile, Dave Sanderling and "Two-Pair" Butford, who overheard Carol talking about Rick's offer while playing cards in the hotel lobby, go to her room and offer her $1,000 for her horse. Dave tells Carol that Rick never even knew her late father until six months ago, and she storms into the bar and berates Rick. The next morning, Dave and Two-Pair go to the track and watch as Manny spurs Gay Fleet to great speeds by singing in its ear. After clocking the horse's impressive time, they realize that Rick has been deliberately holding it back. Dave raises his offer, but Carol decides to keep the horse and engages the crooked Two-Pair as her new trainer. Two-Pair steals Carol's feed to pay his gambling debts and, under Dave's guidance, mistreats Gay Fleet to make the horse run poorly. Carol stubbornly continues to race Gay Fleet, and when the horse consistently comes in last, she grows suspicious. One day, Dave urges Carol to use her dwindling resources to buy another horse in a claiming race, and she decides to claim Rick's horse, Countess Jay, hoping to drive him out of business. Countess Jay collapses and dies after crossing the finish line, however, and Carol is dismayed to learn that she must pay for the dead animal. With her money almost gone, Carol offers to sell Gay Fleet to Dave, but he offers her only a paltry sum. Carol goes to see Rick, who is now romantically involved with Mercedes, and he tells Carol that Dave and Two-Pair cheated her. When Carol confronts Two-Pair, he strikes her, after which Rick beats him up, then proposes a partnership with Carol. As they work to prepare Gay Fleet for the big race, Rick and Carol eventually acknowledge their feelings for each other and kiss. The day before the race, Ma's daughter "Jigger" falls off a horse and breaks her leg, leaving Ma with an enormous hospital bill. Rick asks Mercedes for the money, and she agrees provided that Rick come to work for her as her trainer. Rick realizes he will be a kept man if he goes with Mercedes, but after fighting with Carol, he consents to the arrangement. Carol angrily prepares to return to New York, but when she stops at the hospital to say goodbye to Ma and Jigger, she is surprised to learn that Rick paid their bill with the money he received from Mercedes. Ma and Carol then inform Manny that Carol will place a large bet on Gay Fleet, and the jockey promises the horse will win. Before the race, Rick instructs Manny not to let Gay Fleet win, as he does not want Carol to leave town, but Manny cannot resist, and begins singing to the horse in the final lap. Gay Fleet wins, narrowly beating Dave's horse. Later, Rick prepares to leave town with Mercedes, only to learn that Carol and Ma have already paid off his debt to her. Rick joins Carol, and they decide to marry.