Moving can be tough. Luckily, Henry''s got Mudge, a great big canine buddy, with whom he can share all kinds of adventures! Henry discovers that having a pet is a big responsibility, and he teaches Mudge to sit, heel, and shake his hand. But rolling over is one trick Henry just can't seem to teach Mudge, no matter how hard he tries. When Henry's cousin Annie comes for a visit, Mudge finally rolls over at her command, and Henry thinks Mudge must love Annie more than him. Very upset, Henry runs away to find adventures on his own. Will the two friends be reunited? Find out in this musical, based on the best-selling series of books by Cynthia Rylant.