Former operative Arina Vorobyova dreamed of enjoying peace and quiet in a house in the village and taking a break from hard work. But even here, a terrifying reality overtook Vorobyova. One night her neighbor Alla died. Arina had already participated in the investigation of a similar crime with characteristic traces and evidence, but then the maniac was caught and sent to a maximum security colony. Arina tried to prove to everyone that an innocent person was behind bars, but they simply did not listen to her. And now Arina has to convince herself that she is right. The maniac continues to kill and leave a strange mark of death on the bodies of his victims - a bloody diamond in the area of the heart...