Vienna, 1922: Peter Perg, a former detective, returns to his native city Vienna after seven years in Russian captivity. The former Empire, for which he went to war is shattered. In the young republic, marked by hunger, unemployment and crime, he is a stranger. But then he is surprisingly confronted with a mysterious murder: One of the comrades with whom Perg was in Siberia, has been murdered. He aims to find the murderer of his comrade and to bring them to justice. It turns out that Pergs murdered comrade was not the only victim, but that a serial killer is at work – who systematically tortures his victims according to a principle.