Betragen ungenügend! (1972)

Due to a plot by the teaching staff, headmaster Taft is forced into early retirement and Knörz is appointed headmaster. However, they didn't count on class 13a, and especially not on their spokesperson Pepe Nietnagel. They are anything but happy about losing Taft, their favorite enemy. Without further ado, Pepe and his friends join forces with Taft and hatch a series of daring pranks to get back at Knörz.