"Let's go! Let's go!" The children of class 3a are impatiently waiting for the bus to depart for Burg Borkenstein. But one is still missing! Just in the nick of time, Xaver finally arrives, panting - a welcome opportunity for some of his classmates to tease him about his weight. It seems like everything is conspiring against him: during the bus ride, Xaver struggles with nausea, at Burg Borkenstein he has to share a room with the cheeky Zacharias and his friends, and during the orienteering race, his roommates leave him behind right at the start. Werner Färber authentically and entertainingly describes in his book what can happen on a school trip with third graders. Like in many classes, there is one child in the 3a class community who has a particularly hard time: Xaver. His classmates gradually begin to recognize this.