Grandma Käthe has recently had a helper-and-cleaning syndrome: she takes over a sick acquaintance's job as a housekeeper in the villa of the Lindholm entrepreneurial family. There she immediately clashes with the young and beautiful millionaire's wife Fernanda. The next day, the Brazilian is found dead in the dunes. Murdered! While Fernanda's stalker is an urgent suspect for the criminal investigation department, Grandma Käthe investigates on her own armed with the feather duster to find out more about the victim's family. Curious: No one mourns the unpopular victim. What secret did the Lindholms try to sweep under the carpet? In this four-generation house, everyone behaves strangely. Käthe and her partner Hinnerk, a retired detective, also have a bad time: Hinnerk's sister moves in with the seniors and provides a lot of explosive material. No wonder that Käthe prefers to wipe and vacuum with the millionaires instead of torturing and quarrelling with the rabble at home!