Wilsberg and Ekki are invited to lunch at a moated castle by attorney Dr. Tessa Tilker. When another guest arrives in a car, Tessa is gripped by fear. Out steps Sven Degen, an ex-convict who had vowed to kill Tessa for her role in putting him behind bars back then. As Tessa desperately seeks a hiding place, Wilsberg and Ekki make futile attempts to get rid of Degen.