EU translator Dietmar Lemke's retired parents where CO-asphyxiated at home. Before licensed chimney-sweep Thomas Thiele can confirm it was the result of a badly installed new wood stove, as later confirmed, Thiele makes a most suspicious deadly fool from a rooftop. Thiele also rowed with his wife Sabine, who denies marital troubles, but funded his ailing business, not the first time. The team focuses on Thiele's staff, apprentice Marie Hoffmann and full employee Fabian Kaiser, a recovering drug addict, as well as dirty competition.