Commissioner Oppenheimer has gone underground and must rely on black market dealings to survive. When a brutal murder occurs, his supporter Hilde is arrested, as the victim is her husband, SS Hauptsturmführer Erich Hauser. Although they have been separated for years, Hilde, as a regime opponent, has a motive: the ruthless physician Hauser was a concentration camp doctor in the East and conducted experiments on humans there. Oppenheimer must risk everything to save Hilde from the clutches of the Nazi judiciary. Soon, he discovers clues that a mysterious cult is involved in the murder case.