At a raffle organised by the volunteer fire brigade, the Gützkow family wins a small domestic pig, and although Papa Gützkow is a staunch opponent of pets, he has to admit defeat to the enthusiasm of his children Betty, Zuppi and Tobi. They christen the piglet "Rudi Rüssel", and from then on the grunting four-legged friend is part of the family. But landlord Buselmeier refuses to have a sow in the house and puts the Gützkows out on the street!