Collectable stamps trader Kurt Nietnagel's son Pepe recently transferred from a private boarding school to Mommsen gymnasium (classical high school), but is also already its king of pranksters. Latin teacher Dr. Knörz swears to get rid of Pepe, but a staged suicide means his own exit. Dr. Knörz's replacement, Dr. Kersten, proves a teacher to the rascals' liking. However headmaster Dr. Gottlieb Taft dislikes him for dating his daughter Helena. Now the boys actually come to a teacher's rescue, again trough daring pranks.