Businessman Hannes Burchardt is found dead in the cabin of his yacht, the Constanza. Everything points to a carbon monoxide accident. But upon closer examination, it turns out that he was murdered with dry ice. At first, all the evidence points to his wife, Zola, as the culprit—she wanted a divorce and now stands to benefit from her husband's death. When Nele Fehrenbach's team questions Zola, Zola's lover, organic farmer Michael Jungbluth, intervenes. He is convinced that both the murder and the investigation are part of a conspiracy against him and Zola. Hannes Burchardt, he claims, was deeply entangled in the web of local political corruption and had been conducting shady deals with local political heavyweight Götz Eberlein. When the WaPo refuses to back down, a scandal erupts. Jungbluth and Zola manage to hijack a police boat to force Eberlein and his diligent office manager, Garber, to confess. The WaPo must stop the enraged Jungbluth.

When the WaPo finds the body of a man who's been shot on a rowboat, Nele immediately notices that this case is particularly upsetting to Paul. Paul knows the deceased. He's a convicted robber and murderer. Rudi Maschke robbed a bank 15 years ago. The one million euro haul never turned up. A security guard was killed in the process, leaving behind two children. Paul was part of the task force at the time. Did Maschke go to his ex-girlfriend Maria Ansböck after his release to claim his share of the loot? Maria had broken up with Rudi right after the robbery-murder and now runs a café on the island of Reichenau. His former accomplice, Robin Steffens—who served only seven years and has just returned from Switzerland, now penniless—would also have a motive. But they're too late; he, too, is found dead. Suddenly, Paul himself is in danger. Yet Paul offers Niklas, who has to write an essay for class, a template on the topic of courage.

Shots are fired at the bank on the Reichenau Peninsula. The perpetrators flee in a black boat. Their target is the motor yacht belonging to architect Katrin Ohlschläger, which she wants to sell. The bank robbers, Martin and Harald Draheim, deliberately take the young mother hostage and flee with her. Julia and Jakob immediately give chase, while Paul, annoyed, pores over files.