The poem describes a parent's surprise at their child's sudden change in behavior from mischievous to well-behaved. The child is helping with chores, has clean clothes, and saved their lunch money. The parent questions if the child is an imposter, as it is so unlike their usual rebellious self. Finally, the parent realizes the child must have brought home their school report card, implying it contains bad grades, and the good behavior is an attempt to gain favor.