After Old Tam's untimely death, a litter of puppies was born to his mate, Jeannie, on the ranch in Colorado. Though Gwen had intended to keep the most likely pup for a trial dog, her heart is captured by the runt of the litter, little Punk. Punk is mischief incarnate-again and again, Punk tests Gwen's decision to keep her. But again and again, Punk wins Gwen's heart. Though ridiculed by others, Gwen is determined to turn Punk into a working sheepdog...