When young Mariah sees a darling little puppy named "Princess" at the pet store, she suddenly knows exactly what she wants for Christmas. Before her Christmas wish can come true, she must prove that she can dog-sit Jack, a scraggly rascal of a dog; in fact, the worst dog in the county! Jack turns Mariah and her family's perfect holiday preparations upside down in hilarious ways. It wasn't exactly the Christmas she wished for. Will Jack dash Mariah's hopes for her dream puppy? Or could she get...more than she ever wanted?