D.W. cannot find her blankie and enlists the help of Arthur to search for it, retracing her steps over Elwood City. Mr. Ratburn loses his voice and his sister, Ms. Rodentia Ratburn, substitutes for him. Ms. Ratburn is a kindergarten teacher, and although the class is glad to have some easy work at first, they soon get bored and they realize they miss Mr. Ratburn's tougher classes.