Cal McGill is an Edinburgh-based oceanographer, environmentalist and one-of-a-kind investigator. Using his knowledge of the waves - ocean currents, prevailing winds, shipping records - McGill can track where objects came from or where they've gone. It's a skill that can help solve mysteries ranging from disappearances to murder. Two severed feet wash up on two different islands off the coast of Scotland. Forensics shows that the feet belong to the same body.

Icelandic sisters Áróra and Ísafold live in different countries and aren‘t on speaking terms, but when their mother loses contact with Ísafold, Áróra reluctantly returns to Iceland to find her sister. But she soon realises that her sister isn’t avoiding her...she has disappeared. As she confronts Ísafold’s abusive, drug-dealing boyfriend Björn, and begins to probe her sister’s reclusive neighbours, Áróra is led into an ever-darker web of intrigue and manipulation.

On the day Stockholm police officer Hanna Ahlander’s personal and professional lives crash, she takes refuge at her sister’s lodge in the Swedish ski resort paradise of Åre. But it’s a brief comfort. The entire village is shaken by the sudden vanishing of a local teenage girl. Hanna can’t help but investigate, and while searching for the missing person, she lands a job with the local police department. There she joins forces with Detective Inspector Daniel Lindskog, who has been tasked with finding the girl. Their only lead: a scarf in the snow. 

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.

Trying to process a life crisis Gothenburg policeman, Dennis Wilhelmson, decides to take a trip to his quiet childhood island, Smögen.