Katootje lives in Droogbaak, a very neat municipality. And the neatest people in the whole town are Katootje's father and the neighbor. Katootje, who is almost eight, would like a pet, but she is not allowed to have one, especially not when the queen is visiting Droogbaak and the mayor is organizing a cleanliness competition. So it is not very convenient that her anti-authoritarian aunt Gazeuse and her fiancé, the feisty inventor O.J., unexpectedly come to stay at the Loire. Fortunately for Katootje, things become more fun and exciting at home, and O.J. helps her father in the fight against the cheating neighbor. Still, it takes a while for her father to learn his lesson: there are more important things in life than peace, cleanliness, and regularity.