Mia has just been sacked from the SANS/ State Agency for National Security/ for insubordination and she receives an anonymous tip regarding a horrific ritual murder. As the team delves into a murder investigation, a web of mysteries begins to unravel. The victims were all ritually executed using techniques borrowed from antiquity and the Middle Ages, which may reveal the villain’s true motivation. Reunited with Philip Chanov (Vladimir Karamazov), a former colleague and acquaintance who worked on previous investigations, they find themselves entangled in a multi-layered fraud. The story takes place in the enchanting ancient city of Veliko Tarnovo, which has seen both the greatest acts of bravery and the darkest tragedies. The killer has meticulously selected specific sites throughout this city steeped in myth and tradition, each with its own dark meaning, to carry out the killings. The number of characters in the story grows as more and more people join, each with their own agenda, hidden or otherwise.

Every murder follows a predetermined script and takes place in a specific era. Killing each victim in a ritualistic fashion using execution techniques familiar from antiquity and the Middle Ages reveals something about the villain’s goal. The murderer compares each victim to a well-known Christian monster and leaves notes with them in old languages. In order to help investigators understand the punishment, he points to specific personality traits. The killer picks each murder site in a city full with myth and history for its own unique importance; these choices reveal more about his criminal mind and the reasons he committed the crimes. There is a lot of blood and brutality reminiscent of bygone eras as the killer—an obsessive history buff and nuanced expert of the sources—turns the investigation into a knotted historical mystery.