Cor and Jan are two Dutch students who work in a hospital. A smallpox epidemic has broken out, but the country's capital is occupied by the army. Nevertheless, someone has to go outside the city to get a serum. Cor and Jan steal an old car and make their way through the military lines. It's not easy, but they're smart guys.

Pietje Bell, the famous boy from Rotterdam, goes chicken hunting with his friends Peentje and Engeltje, but they are pursued by a police officer who, despite Aunt Cato's protests, takes them to the police commissioner. Pietje and his friends manage to talk their way out of it. Pietje performs a circus show with his friends Peentje and Engeltje, which is disrupted by a fire when one of Pietje's tricks goes wrong.

Sjors and Sjimmie have received a magic ring as a thank you for their help to a well-known archaeologist. They end up in the Middle Ages with their regular opponents, Boris and Pedro, because of the magic ring. The magic ring makes wishes come true, but Sjors and Sjimmie don't know that. They are accused of witchcraft and are in danger of being burned at the stake.