There's excitement in class 3a: Mrs Besenbinder, the class teacher - known as Besi for short - is supposed to get a present for the move. But why is Leo's class fund suddenly empty? When Tom from class 1b is attacked by older pupils on his way to school, it turns out that Leo's brother is also a victim of the gang and is being blackmailed. Leo has lent him money and promised not to say anything. Headmaster Dieckmann calls in the police, but that's not enough for the 3a pupils. They take matters into their own hands. When an innocent person is harmed in the process, they realise that violence is not a good remedy for violence. In the end, however, the perpetrators are caught. Surprisingly, even with the help of the grumpy caretaker, Mr Pelzig, who apparently doesn't like children. Werner Färber carefully addresses a current topic in this book. Because fear of violence.