After Old Tam's untimely death, a litter of puppies is 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. Not only is Punk the runt of the little, she was born without a beautiful long Border Collie tail, a defect that handler after handler tells Gwen will keep Punk from being able to turn properly.
Furthermore, Punk is mischief incarnate-again and again, Punk tests Gwen's decision to keep her, rather than her lovely littermate Lark, pushing Gwen's patience to the max; but again and again, Punk wins Gwen's heart. Though ridiculed by others, Gwen decides to teach Punk to handle sheep and takes her to sheepdog trials. In her quest to train Punk, Gwen discovers an old friend is a very good friend indeed.
