In the heart of Madrid, a spirited girl and her brother Manolo scrape by with only two loyal horses and a dream. Disguised as a boy, she works the streets by day and trains Cabriola by night—hoping to turn the horse into a bullfighting legend. When she meets her idol, famed matador Ángel Peralta, her secret identity opens the door to the ring. As “the Boy” and Cabriola rise through the ranks of comic bullfighting, fame grows—but so does the risk of discovery.