Everyone in River Heights has shown up to watch Katie McCabe try to beat the world record for the Dance-A-Thon game. Judges are coming to the arcade to see how quickly she can spin across the electronic dance floor and how many points she can win.

But just as Katie's about to get ready, she notices her lucky headband has gone missing! She always wears the blue, sparkly headband when she competes and knows she'll bomb without it. Luckily, Nancy takes her Clue Book everywhere. Nancy, Bess, and George are on the case! Who is sabotaging Katie's big day? Could it be the owner of the rival arcade, Michael Parker, who wanted the judges to see his world record sock attempt? Or May Bensen, the current Dance-A-Thon record holder? It's up to the Clue Crew--and you--to find out!