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.

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.

When 19-year-old Iselin Hanssen disappears during a run in a popular hiking area in Bodø, Northern Norway, suspicion quickly falls on her boyfriend. For investigator Jakob Weber, the case seems clear-cut, almost unexceptional, even though there is some suggestion that Iselin lived parts of her life beneath the radar of both family and friends. But events take a dramatic turn when another woman disappears in similar circumstances - this time on the island of Røst, hundreds of miles off the coast, in the wild ocean.

When a body of a woman is discovered at a lighthouse in the Icelandic town of Akranes, it soon becomes clear that she’s no stranger to the area. Chief Investigating Officer Elma, who has returned to Akranes following a failed relationship, and her collegues Sævar and Hörður commence an uneasy investigation which uncovers a shocking secret in the dead woman’s past that continues to reverberate in the present day.