A mouse named Wemberly, who worries about everything, finds that she has a whole list of things to worry about when she faces the first day of nursery school.
Lilly loves everything about school, especially her teacher, but when he asks her to wait a while before showing her new purse, she does something for which she is very sorry later.
Seven-year-old Billy Miller starts second grade with a bump on his head and a lot of worries, but by the end of the year he has developed good relationships with his teacher, his little sister, and his parents and learned many important lessons.