K3 are going to Bavaria for the opening of a new castle nightclub. Maxine entrusts them with her nephew, Maxou, who proves to be a harder babysitting challenge then the girls expected. He's such a troublemaker, that K3 get angry and yell at him. As soon as the girls find out that there is talk of a scary monster in the castle nightclub, they look for Maxou only to discover he ran away. Will K3 be able to find Maxou before the monster does? Or is K3's failed babysitting career the least of their worries?