Katharine is excited when her homemade popcorn bowl is in the school’s art auction, but a misunderstanding with another third grader causes her to start a bidding war that turns the charity event into a competition fueled by greed. This book concentrates on the jealousy Katharine feels toward her classmate Vanessa (Miss Priss-a-Poo), but it also reveals her compassionate side by including a secondary story line involving her cousin, whose parents have recently divorced.