Eva Magnus and her daughter are out walking by the river when a man's body floats to the water's surface. Eva goes to call the police, but when she reaches the phone, she dials another number altogether.

One mild summer evening Lily and her husband are enjoying a meal while their baby daughter sleeps peacefully in her pram beneath a maple tree. But when Lily steps outside she is paralysed with terror. The child is bathed in blood. Inspector Sejer is called to the hospital to meet the family. Mercifully, the baby is unharmed, but her parents are deeply shaken, and Sejer spends the evening trying to comprehend why anyone would carry out such a sinister prank.

Oslo, 2018. Former long-distance runner Sonja Nordstrøm never shows at the launch of her controversial autobiography, Always Number One. When celebrity blogger Emma Ramm visits Nordstrøm’s home later that day, she finds the door unlocked and signs of a struggle inside. A bib with the number one has been pinned to the TV. Police officer Alexander Blix is appointed to head up the missing-persons investigation, but he still bears the emotional scars of a hostage situation 19 years earlier, when he killed the father of a five-year-old girl.

When a young woman is found lying half-naked in the snow, bleeding and unconscious, and a highly esteemed, elderly writer falls to his death in the local theater, Ari is dragged straight into the heart of a community where he can trust no one and secrets and lies are a way of life. Past plays tag with the present and the claustrophobic tension mounts as Ari is thrust ever deeper into his own darkness - blinded by snow and with a killer on the loose.

At a former sanatorium in the north of Iceland, now a hospital ward, an old nurse, Yrsa, is found murdered. Detective Hulda Hermannsdottir and her boss, Sverrir, are sent to investigate her death. There, they discover five suspects: the chief physician, two junior nurses, a young doctor, and the caretaker, who is arrested following false testimony from one of the nurses, but subsequently released. Less than a week after the murder, the chief physician, is also found dead, having apparently fallen from a balcony.