A young Czech girl, missing for eight days, is found abandoned in a deserted playground. She is so traumatized she cannot speak. DCI Eve Clay is on her way to interview the victim, when another case is called in. Two Polish migrant workers have been found dead in their burnt out flat. But Clay soon realizes that this is no normal house fire. The men's bodies were set alight, after the killer had clinically removed both of their hearts. Then reports come in that the Czech girl's mother has now also disappeared. As Clay and her team work to make sense of these crimes, they receive a call saying there will be another murder before the day ends. And this time, the body count will only go up.