In the quiet Carpathian village of Yaseni, a series of brutal murders unfolds. A Kyiv detective, Markiyan Sych, comes to the village for rehabilitation after being wounded, and unwittingly finds himself in the middle of the investigation along with a young local policeman, Ivan Basyuk. The locals are convinced that evil spirits and a mysterious creature from ancient legends, Mara, are behind everything. Step by step, the investigation reveals the dark past of the village, the hidden fears of the inhabitants, ancient secrets and long-forgotten events that intertwine in a terrifying web. But whose hands are behind this rage - human or something much more otherworldly?
