When Denise Dunleavy, the snootiest girl in the fifth grade, invites herself over to Polly's house, Polly is worried. Denise doesn't know anything about Polly's supernaturally spooky stepfamily, the Kreeps, and Polly wants to keep it that way. But things go from bad to worse when Denise develops a crush on Polly's older stepbrother, Vincent. Now she won't stop coming over! Can Polly cure her crush before Denise discovers the truth about the Kreeps?