The Cologne Commissioner Gereon Rath (Volker Bruch) finds in the capital with his colleague Bruno Wolter (Peter Kurth) against a pornoring. After a raid, he encounters a photo that takes his case in a new direction. In the presidency, he meets the stenographer Charlotte Ritter (Liv Lisa Fries), who keeps her family above her with police suits. In an attack on a freight train, Russian revolutionaries are attached to a car with brisan content to be smuggled to Berlin.