Snot and Splash travel to their grandmother's house in the small town of Mouthwash for a winter holiday. Once there, they discover that everything is a little off in what used to be a very ordinary town. The strangest thing is that holes are disappearing from the town. Snot and Splash set out to investigate and manage to get on the trail of a local dentist, Migrén Junior. However, the investigation is in danger of failing when messy Snot and diligent Splash get into an argument with each other. How can Mouthwash be restored and the holes put back in place if the boys can't work together? The only way to restore the world is for the brothers to work together.