Küßchen und der General (1961)

The group council leader of 7b, Punkt, has a hard time because General sets the tone in the class - with stupid pranks. The new kid, Küßchen, is quite different. He likes tinkering and has his own field telephone. General and his gang want to get one over on him and build a pitfall, but it's not Küßchen who falls in, but a lieutenant from the NVA. He breaks his arm and Küßchen visits him in hospital. Betrayal, the others think. But the two become friends and the lieutenant helps the children build an amateur radio station. The general who joins them is interested. He entices Küßchen to use the radio illegally, which brings the police onto the scene. And now the general shows that he is a decent guy after all.