Darby Carter loves horses, even though she's never actually ridden one. Darby's grandfather is an expert riderâin fact, he owns a horse ranch in Hawaii. So when he agrees to take her inâalong with the beautiful mustang Darby saved on the range in Nevadaâshe knows she can't refuse, even if she is a little terrified! But Darby's filly arrives in bad shape, and Darby's grandfather wonders if the wild horse will ever trust a human again. Can Darby take the reins and save her horseâor has she lost the mustang forever?