A six-year-old girl is found in the Norwegian countryside, hanging lifeless from a tree and dressed in strange doll's clothes. Around her neck is a sign that says, "I'm traveling alone." A special homicide unit in Oslo reopens with veteran police investigator Holger Munch at the helm. Holger's first step is to persuade the brilliant but haunted investigator Mia Krüger, who has been living on an isolated island, overcome by memories of her past.

When a young woman is found brutally murdered in her own apartment with an intricate pattern of lines carved into her face, Copenhagen police detectives Jeppe Korner and Anette Werner are assigned to the case. Soon, they establish a link between the victim, Julie Stender, and her landlady, Esther de Laurenti, who’s a bit too fond of drink and the host of raucous dinner parties with her artist friends. Esther also turns out to be a budding novelist - and when Julie turns up as a murder victim in the unfinished mystery she’s writing, the link between fiction and real life grows.

In a Stockholm city park, police discover the hideously abused body of a young boy. Detective Superintendent Jeanette Kihlberg heads the investigation, battling an apathetic prosecutor and a bureaucratic police force unwilling to devote resources to solving the murder of a nameless immigrant child. But with the discovery of two more mutilated children's corpses, it becomes clear that a serial killer is at large.

Seventeen years ago, Criminal Inspector Ewert Grens was called to the scene of a brutal crime. A family had been murdered, and the only survivor - and witness - was the five-year-old daughter. The girl was placed in the witness protection program, and the case went cold, but years later, Grens is still haunted by the seemingly random slaying and the little girl who was spared. So when he learns that the apartment where the crime occurred is now the scene of a mysterious break-in, Grens immediately fears that someone is intent on silencing the only witness.

The police are desperate for information on the triple homicide. Detective Joona Linna enlists the help of hypnotist Erik Maria Bark. But when Bark unlocks the secrets in the boy’s memory, he triggers a terrifying chain of events that will put all their lives in jeopardy.

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 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.

The story opens with the apparently accidental drowning of a sixth form student in the Norfolk countryside. As a matter of routine, or so it seems, the case passes across the desk of Detective Sergeant Smith, recently returned to work after an internal investigation into another case that has led to tensions between officers at Kings Lake police headquarters. As an ex-DCI, Smith could have retired by now, and it is clear that some of his superiors wish that he would do so.

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.

Five years ago, DCI John Lomond led the search for notorious Glasgow child-killer ‘The Sandman', until personal tragedy forced him off the case. In Lomond's absence, the killer was never found. Now, with nothing but work left in his life, Lomond remains obsessed with the case–despite the nightmares it brings. When a child is abducted in similar Sandman fashion from an affluent Glasgow suburb, Lomond is brought in to find them before it's too late.

D.I. Duncan McAdam is dispatched home to the Misty Isle. A body has been found buried in a remote location on the Waternish peninsula. Well-preserved in the peat, Isla Matheson—missing for the better part of two decades—is revealed to a shocked island community. A teenage runaway is dead...and no one is talking.

Everyone has secrets, and Rachel Holloway is no exception. She’s worked hard to keep the past where it belongs: dead and buried. And so far, she’s been very successful. But now the small newspaper where she works wants to produce a podcast on a cold case: the disappearance 12 years ago of young Molly Forster. Some secrets should never see the light of day, and, as far as Rachel is concerned, whatever happened to little Molly is one of them.

Former soldier. Ex-copper. Current man on the edge. Shunned by his old colleagues, and dividing his time between a dead-end job and the bottom of a whisky bottle, former Police Scotland detective superintendent Bob Hoon’s life is a mess. Then an old face from Hoon’s Special Forces days turns up asking for help: His teenage daughter has been missing for months, the police have drawn a blank, and he needs the kind of help that only Hoon can provide. And besides, Hoon owes him one.

Iceland, 1956. Fourteen-year-old Lára decides to spend the summer working for a couple on the small island of Videy, just off the coast of Reykjavík. In early August, the girl disappears without a trace. Time passes, and the mystery becomes Iceland‘s most infamous unsolved case. What happened to the young girl? Is she still alive? Did she leave the island, or did something happen to her there? Thirty years later, as the city of Reykjavík celebrates its 200th anniversary, journalist Valur Robertsson begins his own investigation into Lára's case.

The body of a young Russian woman washes up on an Icelandic shore. After a cursory investigation, the death is declared a suicide and the case is quietly closed. Over a year later Detective Inspector Hulda Hermannsdóttir of the Reykjavík police is forced into early retirement at 64. She dreads the loneliness, and the memories of her dark past that threaten to come back to haunt her. But before she leaves she is given two weeks to solve a single cold case of her choice.