Try as they might, Nick and Sally just can't learn to do a somersault. Luckily the Cat's friend Luis the armadillo is the king of the roly-polys! But when they find Luis, they learn that he only rolls when he gets surprised. They take turns trying to surprise him, and when they finally do, they're the ones surprised when they learn that not only can Luis roll, but he also can run underwater! Back at home, they follow Luis's advice and are now able to somersault!