Investigator Sofia Kovic has uncovered a connection between several deaths in Oslo over the last year and a half. She tries to call her superior, Alexander Blix, but before Blix has time to return her call, Kovic is shot and killed in her own home. In the apartment below, Blix's daughter Iselin narrowly escapes becoming the killer's next victim. Four days later, Blix and online crime journalist Emma Ramm are locked inside an interrogation room, facing the National Criminal Investigation Service. Blix has shot and killed a man, and Ramm saw it all happen. In the hospital, Iselin's life hangs in the balance. Blix no longer knows who he can trust. And he's not even certain he's killed the right man . . .