"I don't want to grow up!" Jenny protests. She insists on pretending to be a horse, as she has since kindergarten. However, in seventh grade, others expect Jenny to acquire the trappings of adulthood. She balks, refusing to be saddled with other people's notions of maturity. As friends begin to doubt her and boys start to notice her, Jenny must tame her inner horse. Her solution is a dandy one.