Racing Blood

The Shady Knolls horse ranch, which is owned by "Mitch" Mitchell and his daughter Lucille, is managed by Tex. Teenager David and old-timer Gramps are part of Tex's crew. When Mitch announces that a mare, Cheetah, is carrying the offspring of his prize horse Ghengis, the ranch hands eagerly anticipate the new arrival. Late one night, David watches through a hole in the stable wall as Cheetah delivers identical twin colts. However, one is born with a deformed, split hoof which will not heal, prompting Doc Nelson, the veterinarian, to recommend that the colt be destroyed. When Gramps is assigned to shoot the colt, David pleads with him to spare its life. Gramps relents, and after he and David hide the colt in their cabin, they trick Mitch and Tex into believing that the animal has been disposed of. David names the colt "Mr. Marker" and tells Gramps that one day he will enter him in races. Meanwhile, Lucille, who enjoys flirting with Tex, tells him that her father has given her the other colt, "Satan," to race under her own colors. One day, while Gramps and Tex are out mending fences, Mr. Marker escapes from the cabin and briefly joins Cheetah and Satan in the pasture until Gramps recaptures him. Four months after Mr. Marker's birth, David tells Doc Nelson that he is still alive and arranges for him to examine the colt at his office. After Doc congratulates David and Gramps on what they have accomplished with the horse's development, he x-rays the hoof and puts a corrective, lightweight shoe on it, then advises them that the horse needs pasture and exercise. David and Gramps decide to move Mr. Marker to a box canyon and, for a night or two, sleep with him to keep him company. Tex has assigned David to take over the care of Satan, but the first time David attempts to ride him, the horse throws him. David later decides to ride Mr. Marker and, when Gramps is unable to deliver a saddle, David manages to ride the colt bareback. Doc follows Mr. Marker's development and tells David that the horse is not ready for racing because his leg needs to be strengthened. He recommends riding the horse in surf, which David does. Doc also tells David that Mr. Marker needs to be stabled at a regular training farm if he is going to race against professionals. David then decides to darken Mr. Marker's white blaze, identical to that of Satan, and pass him off as a horse he and Gramps have acquired. They then secure permission from Mitch to stable the horse at Shady Knolls. One day, Mitch, unaware that David is out riding Satan, assigns his jockey, Wee Willie, to ride the horse in a timed trial. As Mr. Marker is wearing a protective covering over the blaze area, the jockey mistakes him for Satan and rides him. Mitch, Tex and Lucille are delighted when "Satan" beats his own time record and David is thrilled when the jockey tells him the horse has great potential. Later, as David and Gramps are discussing how to raise money to enter Mr. Marker in an upcoming race, Tex overhears them, examines the horse, and then tells them that he knows their secret. Tex agrees to help them, offering to pay the entry fee and arrange for a jockey, as David is too young to ride in the race. On the day of the big race, Mitch and Gramps make friendly wagers with Tex and Lucille on the feature race in which both Mr. Marker and Satan will compete. David tells his jockey, Ben Carson, about a secret whistle he uses to spur Mr. Marker on. When the race begins, Satan takes the lead, is passed by Mr. Marker then regains the lead. When Ben is unable to replicate the secret whistle, David reproduces the sound and Mr. Marker wins, with Satan coming in second. David and Gramps then tell Mitch the truth about Mr. Marker and that the horse really belongs to him. Mitch is so pleased at having bred and trained both the winner and runner-up in the important race that he gives Mr. Marker to David and Gramps. Lucille pays off her wager to Tex, who bet on Mr. Marker, but ultimately wins when Tex suggests that they get married.