The only witness to a shocking murder is the victim's ten-year-old daughter, Margret. The police turn to the Children's House for their expertise in childhood trauma. The manager Freyja doesn't much like the police - especially the detective in charge, Huldar. But she does want to help them protect Margret. And when more people die - their murders heralded by strange messages, texts, and strings of numbers - they will have to work together to crack the riddle before they become targets themselves.