A stern but sentimental lady at heart, "the house torturer" Fröken Hildur Bock, appears in Malych (Gamin). She immediately becomes the all-powerful boss of the apartment and installs her favorite Mathilde, a fat and big cat. Malych is unhappy because of Fröken Bock's perpetual bans and decides to take revenge. Who will help him if not his old friend Karlsson who has given himself the title of "house torturer tamer".