Felix (Oskar Keymar), eleven years old, has been rejected by various schools and now has one final opportunity at the Otto Leonhard school. However, there is little hope on the first day. But its new Director and teacher Dr. Schmitt Gössenwein is irritating and the boys in his class call him above all, the arrogant Mario (Georg Sulzer), not welcome. Felix must pass many tests of bravery in order to be accepted by them. The first is that it occurs after school in the evening. When Mrs. Schmitt Gössenwein tried to catch him, he was captured by everyone.