Our four heroes from Super Monkey Ball - Aiai, Meemee, Baby and Gongon - were enjoying a typical day, when they saw a flying machine crash down on a nearby island. Soon, they discovered that the mysterious Naysayers have appeared, spreading discord and unhappiness all over the island. And to top it all off, the prince and princess of the neighboring islands have gone missing on Jungle Island - if they aren't found and returned, there's sure to be trouble! Can our heroes restore order to Monearth?