Crime observer of the Press Center of the Central Internal Affairs Directorate of the Moscow Region Ekaterina Petrovskaya comes to the scientific town of EREB near Moscow. In Greek mythology, Erebus is the Eternal Darkness. Son of Chaos and Darkness. Is it any wonder that a series of monstrous crimes take place in the town - women are brutally killed, and their bodies are dressed in carnival costumes of flies. Katya gets involved in a complex and dangerous investigation. It is led by the head of the local police department, whose last name, by a strange coincidence, is Alla Mukhina. And on the very first day, Katya meets the charismatic ex-cosmonaut Konstantin Cheglakov, who paints scary pictures of outer space. It is in his house that Katya encounters the first riddle thrown in by Erebus, generous with secrets...