At the Upside Down Amusement Park – it’s Grandparent Hall of Fame Celebration Day. All the kids and their grandparents – EXCEPT one little girl – are having tons of fun riding the Upside Down Roller Coaster, Upside Down Merry-Go-Round, Upside Down Ferris Wheel and eating lots of Upside Down Buckets of popcorn!

But…..this one little girl can’t have any fun UNTIL she solves a really important mystery!