Jakob is the first to sense the danger. Tammy's mother, Sonja, has never let her daughter down. Now she's ignoring Jakob's call, even though she was supposed to have been back at Villa Fehrenbach 24 hours ago. Of all people, Julia supports her ex-boyfriend Jakob in his desire to track Sonja's cell phone, while Nele is still hesitating. A visit to the art expert and collector Ruben von Wallersleben reveals the unsettling fact that, until recently, Sonja had been restoring an Otto Dix painting—one that has just been discovered under strange circumstances and is worth millions.

It's the perfect evening: As Julien Bakker speeds across Lake Constance in a motorboat with his beautiful companion after a visit to the lakeside terraces, they're both tipsy and have eyes only for each other. They hear the desperate cries of a rubber boat driver too late. Because he doesn't want his affair with his companion, Flora Fitz, to be exposed—and because he's also under the influence of alcohol—Bakker flees the scene of the crime. There's no trace of the rubber boat's driver. He keeps the accident a secret from his wife, Annika. Instead, he finds a blackmail letter on his car the next morning…

A gorgeous morning on Lake Constance. Lea von Brahms sets out on her daily 2,000-meter swim. But she never makes it back to shore. Despite her desperate struggle, something drags her down into the depths. At first, Nele and Paul suspect Lea's boyfriend, the attractive personal trainer Malte Hummert.