Nancy, Bess, and George are having a blast at the River Heights Carnival, sampling yummy snacks and trying to win prizes. Most of all, the girls cant wait for their favorite local singing star, Isabelle Santoro, to perform. But Isabelle may cancel if she finds out that someones ruining all the fun with really annoying pranks. Snooty Brenda Carlton, annoying Orson Wong, and Chloe Cruncher Mondesky, the pie-contest queen, all make good suspects. Nancys clue book is filling up, and shes got to solve this puzzle fastso the fun, and the show, can go on!