Ben thinks his great-uncle is a real idiot, a complete fool. But whether the boy likes it or not, he has to put up with this man in his ridiculous corduroy pants and his terrible habits for a while. At the beginning of the summer holidays, Ben's mother suddenly ends up in a hospital far away after a car accident. Great-uncle Horst, who is just as unfamiliar with a ten-year-old boy, now has to take care of Ben. However, he is unwilling to give up his usual afternoon nap, his canned food, and his aversion to the word "cool" – conflict is inevitable! Ben can't just run away, as that would only worry his sick mother even more. So, he has to grit his teeth and get through it! Over time, Ben discovers that Horst, who does quite a lot with his two friends of the same age, isn't such an idiot after all. And Horst realizes that not everything is as it seems.