As usual, Egon has an ingenious plan. And, as usual, it works just fine until one of the gang members makes some kind of funny error. This time, however, even Egon's life is in danger, for some international criminals try to get rid of him by throwing him into a container filled with acid.
A bunch of wagons are crossing the border. It's the Karla Circus, which, after a rough season in Germany, is gonna try its luck in Denmark. Mrs. Karla, the beloved and respected circus director, goes through passports and papers with the customs officers... everything's fine, so the circus caravan can keep going to the next town. One of the circus employees is caught harboring a vagrant in his wagon. But when it turns out that the vagrant is an excellent flute player, he becomes an asset to Circus Karla.
The young headmaster of a boy's boarding school has decided that due to the virility of his young charges, they are a sort of national treasure. He believes that his school should become co-educational as soon as possible. In order to raise funds for the changeover, the boys stay behind during their summer vacation and temporarily convert the school into a love hotel.
