It's May and the snow has hardly melted in Gêteborg, Sweden, but things are heating up quickly for Detective Inspector Irene Huss in the Violent Crimes Unit. The body of a teenage girl is found in the woods, naked and horrifically scarred. Then a second young girl is found, wearing what appears to be the other half of the lingerie set recovered near the first body. Fearing the two cases are linked and that the killer may strike again, Irene and her colleagues embark on a desperate hunt that takes them deep into a shadowy world of online predators.