Summary Jakob is the first to sense the danger. Tammy's mother Sonja has never let her daughter down. Now she rejects Jakob's call, even though she should have been back at Villa Fehrenbach 24 hours ago. Julia, of all people, supports her ex-boyfriend Jakob in his wish to locate Sonja's cell phone, while Nele is still hesitant. A visit to the art expert and collector Ruben von Wallersleben brings the disturbing realization that Sonja was recently restoring an Otto Dix painting that was just discovered in a strange way and is worth millions. Sonja left in the water taxi, the serious man says - and Jakob realizes that Sonja did not want to go back to her daughter and him, but to the gallery owner Isabell Herold in Konstanz. Meanwhile, Mechthild realizes that the picture of an "evil woman" that Tammy is currently painting could help in the search for Sonja. A visitor to the Herold Gallery, who Tammy's picture fits, sneaks off when Paul and Julia show up there. They soon find Karin Pleyer, who attacked Sonja once before in Frankfurt and who has a desperate motive. But then Julia discovers that the water taxi driver Giulio Lemke has a record of tying up women. When he is brought to the station, Jakob almost goes crazy and Nele makes a difficult decision. Only slowly does it dawn on the police what could be behind Sonja's disappearance. They race in the boat to a group of buoys. Shots echo across the lake. Jakob aims.

• Crime