Elsbeth, Karin and Ursel have been friends for ages and are now enjoying their retirement in a pretty Art Nouveau villa on the Baltic Sea beach in Schönberg. But when they want to stock up on fresh crime fiction again, they find the bookseller Jan dead to their horror. The passionate 'Tatort' expert Karin immediately sees that he did not die of natural causes. For the second time within a year, the three ladies are involved in a crime. After the police arrive, she rushes home to talk shop about the murder with her roommate Olaf, a retired inspector. But there is no trace of Olaf, and the three amateur detectives are afraid of evil ...