Wilsberg and Ekki are invited by lawyer Dr. Tessa Tilker to lunch at a picturesque water castle. However, the mood shifts dramatically when another guest arrives: Sven Degen, a former criminal who once vowed to kill Tessa. This unexpected encounter throws Tessa into a state of panic, and she quickly hides to protect herself. Meanwhile, Wilsberg and Ekki struggle to resolve the tense situation as they attempt, unsuccessfully, to persuade Degen to leave.