An unidentified corpse

Because a witness failed to appear at the police station despite being summoned, Hubert and Girwidz want to search for the man. Too late—he is found dead in the sewage tank, his workplace. Sewage treatment plant manager Ulrike Mettmann assumes it was a tragic accident. But it quickly becomes clear that someone helped him along. When it also turns out that the tap water is contaminated, a state of emergency is declared in Wolfratshausen. For Hubert, however, this warning comes too late. He has already drunk the contaminated water...