Southern Sweden: Beautiful countryside, endless forests, coastal walks, dark days - and even darker nights. But beneath the beauty lies a dark heart... Skåne, 1986: On the night of Walpurgis, the eve of May Day, where bonfires are lit to ward off evil spirits and preparations are made to celebrate the renewal of spring, a sixteen-year-old girl is ritualistically murdered in the woods beside a castle. Her stepbrother is convicted of the terrible deed and shortly after, the entire family vanishes without a trace.

Detective Inspector Karen Eiken Hornby has returned to the main island, Heimö, after many years in London and has worked hard to become one of the few female police officers in Doggerland. So, when she wakes up in a hotel room next to her boss, Jounas Smeed, she knows she's made a big mistake. But things are about to get worse: later that day, Jounas's ex-wife is found brutally murdered. And Karen is the only one who can give him an alibi.

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.

DS Rakesh Siyal is an idealist. Frustrated as an Edinburgh human rights lawyer, he joins the police, determined to solve the problems he sees with the criminal justice system from the inside, rather than out. His first day as a cop sees him sent down to Galashiels in the Scottish Borders, where he’s given a simple task – return a suspect to Glasgow to face justice.

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