When his widowed father Bart Connors decides to remarry and go away on a honeymoon, Jackie Connors, a lonely ten-year-old boy, is sent to spend the summer at the horse training ranch owned by his grandfather, "Captain" Chris Connors. Jackie, whose mother died when he was three, the same year he suffered a crippling bout of polio, has forged a strong bond with his dog Hansel, who he feels is his only friend. When Captain asks Jackie why he named the dog after a character in a fairy tale, the boy replies that fairy tales are preferable to the grim realities of death and disease. Soon after, the strong-willed Leslie Macdonald comes to stay at the ranch with her thoroughbred North Wind, who has been depressed ever since the loss of his dog companion. Leslie, who bred North Wind and is bent on proving his superior blood line, has brought the horse to the ranch in hopes that a change of scenery will snap the animal out of his depression. After Ben, the ranch cook, tells Jackie the legend of a treasure hidden by bandits in the foothills, Jackie and Hansel go to search for it. In the hills, a rattlesnake springs from the rocks and bites Hansel, but Captain gives the dog a shot of anti-venom antidote, thus saving his life. Later, Captain asks Leslie about her estranged husband Bill, and when she tells him that Bill slapped her after she struck him during an argument about her devotion to North Wind, Captain lectures her about the tenets of a successful marriage. One night, the wind picks up, terrifying North Wind, who bolts from his stable. When Hansel chases after the spooked steed and calms him, North Wind befriends the dog and is no longer a sad horse. At summer's end, Bart and his new wife Shelia come to take Jackie home, but the boy insists on staying with his grandfather. After Captain advises Bart to give his son a little more time, the newlyweds drive off. Afterward, Leslie asks Jackie to sell her Hansel as a companion for North Wind, but Jackie adamantly maintains that the dog is not for sale. Soon after, Bill, who has been invited by Captain, arrives at the ranch, where Leslie coolly informs him that she plans to file for divorce because their marriage was a mistake. The next day, North Wind's trainer Jonas comes to take the horse home and Bill tries to explain to Leslie that Jackie's need for his dog is greater than North Wind's. Ignoring Bill's advice, Leslie offers to set up a $5,000 trust fund for Jackie in exchange for his dog. When Jackie overhears that Captain has agreed to the arrangement, he decides to run off and find the treasure, thus alleviating the need for Leslie's money. As the afternoon wears on, the adults begin to worry about the missing Jackie, and, at sunset, Captain mounts his horse to search for the boy. Meanwhile, deep in the woods, Jackie and Hansel are stalked by a mountain lion, and when Jackie grabs Hansel and starts running, he trips and falls down the hillside. Just as the mountain lion is ready to attack, Ben, who has been conducting his own search for Jackie, fires his rifle and slays the beast. Captain then takes Jackie and Hansel back to the ranch, and the next morning, Bill blames Leslie for putting the boy in peril. After Bill forces Leslie to face her obstinacy and recognize that he truly loves her, they reconcile. Meanwhile, in Jackie's room, Captain tries to convince the boy to give Hansel to the lonely horse. After Captain leaves, Jackie decides that North Wind needs Hansel more than he does and offers Leslie the dog as a present. When Leslie refuses Jackie's offer, North Wind whinnies at Hansel, who then wags his tail at the horse, prompting Jackie to carry him into the horse's trailer. After North Wind's trailer drives off, Bart and Shelia come to take Jackie home, and the boy eagerly joins them.