Fear is spreading in Karlsruhe: For weeks, a serial killer has been on the loose in the Hardtwald, near the district of Waldstadt. Time and again, under the cover of night, the same wire noose is quickly and mercilessly tightened around the necks of unsuspecting victims, whom the perpetrator seemingly selects at random. Chief Inspector Oskar Lindt, leading a large special commission, is following hundreds of leads without any significant results. His opponent seems overpowering, and the fear among the population is growing. Additionally, a body has been reported found in the nearby Black Forest, and the signature of the noose killer is unmistakable on this victim as well.