WaPo Bodensee

After a tryst at a hotel in Konstanz, Walter Tesker drives his car at high speed into the lake without braking. The WaPo manages to rescue him at the last second. While Tesker is placed in an induced coma at the hospital, the WaPo discovers that the car's software had been tampered with. The accident turns out to be an assassination attempt. Through a receipt from a lingerie boutique, Jakob tracks down the woman from the hotel: Sandra Murau claims that she had been having an affair with Tesker for two months and now wants to save her marriage to her husband, Michael. The case takes a new turn when Nele receives a visit from the Office for the Protection of the Constitution, which informs her that Tesker was a former Polish spy who betrayed several colleagues after the fall of the Berlin Wall and had been living in Switzerland with the Office's knowledge. The case is none of the WaPo's business. But to Paul's great relief, Nele has no intention of handing the investigation over to anyone else. She tracks down Oleg Gorski, a former colleague of Tesker's, who is currently undergoing cancer treatment on Lake Constance. Nika Murau surprises her parents with the news that she's dropping out of college.

When even the newspapers start reporting on the "Phantom of Lake Constance" on their front pages, District Attorney Dr. Severin loses his temper. He storms into Nele's office and accuses her of not having her department under control. Meanwhile, the WaPo is even working night shifts to track down the person who has now broken into and robbed nine yachts along Lake Constance. Each time, the perpetrator left no traces and wasn't caught on camera. Then a sailor, Max Gerber, comes forward, saying he saw the Phantom in the semi-darkness before he was incapacitated.

A boat drifting aimlessly holds a nasty surprise for Julia and Paul during their patrol across the lake. There is a dead body on board. Investigators suspect suicide after finding a gun next to the body of Michael Schwab. That is the name on the papers found with the body, and it is also the name of the man whom Nora Fornoni reports missing to Nele at the police station almost at the same time. When Jakob later tries to get more detailed information from Nora, who works as a waitress at a beach bar, he finds her locked up and being threatened by her boss, Oliver Baier.

The picnic by the lake with the beautiful tour guide Alina Poll ends fatally for Max Rogall. The real estate agent collapses, bleeding, in front of beachgoers. Nele and her team are in the dark. After all, Rogall was rich, had no enemies, and his wallet is full. Paul finds the victim's car and, in the GPS, a lead pointing to David Petrov. The businessman seems genuinely distraught over Rogall's death and, moreover, has an alibi from his assistant, Mascha. Rogall died from a fatal blow to the heart. Was it a defensive strike by Alina Poll, who felt threatened by the man who might be her father?