Beneath the imposing Kollen Mountain lies a small village where the children run in and out of one another's houses and play unafraid in the streets. But the sleepy village is like a pond through which not enough water runs - beneath the surface it is beginning to stagnate. When a naked body is found by the lake at the top of the mountain, its seeming tranquillity is disturbed forever. Enter Inspector Sejer, a tough, no-nonsense policeman whose own life is tinged by sadness.

Has anyone seen Andreas? Andreas's disappearance is a mystery to all, including his inseparable friend Zipp. But its not easy for Zipp to come forward with details of the last time he saw his friend - they had been following an old woman, an easy target for some quick cash, and Andreas boldly followed her into her home brandishing his knife, the next moment he was gone.

Ida Joner gets on her brand-new bike and sets off to buy sweets. A good-natured, happy girl, she is looking forward to her 10th birthday. Thirty-five minutes after Ida should have come home, Helga Joner, her mother, starts to worry. She phones the shop and various friends, but no one has seen her daughter.

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.

'He'd just learnt to walk,’ she said. ‘He was sitting playing on his blanket, then all of a sudden he was gone.’ A 16-month-old boy is found drowned in a pond right by his home. Chief Inspector Sejer is called to the scene, as there is something troubling about the mother’s story. As even her own family turns against her, Sejer is determined to get to the truth.

Gunder Jomann, a quiet, middle-aged man from a peaceful Norwegian community, thinks his life has been made complete when he returns from a trip to India a married man. But on the day his Indian bride is due to join him, he is called to the hospital to his sister's bedside. The local taxi driver sent instead to meet the bride at the airport returns without her. Then the town is shocked by the news of an Indian woman found bludgeoned to death in a nearby meadow.

Charlo Torp has problems. He’s grieving for his late wife, he’s lost his job, and gambling debts have alienated him from his teenage daughter. Desperate, his solution is to rob an elderly woman of her money and silverware. But Harriet Krohn fights back, and Charlo loses control. Wracked with guilt, Charlo attempts to rebuild his life. But the police are catching up with him, and Inspector Konrad Sejer has never lost a case yet.

A mother and child are found brutally murdered in an old caravan on a remote piece of land. A bloody footprint is discovered at the scene, and Chief Inspector Sejer is called to investigate. Meanwhile another mother, dying of cancer, confesses to her 21-year-old son that he is adopted. The man who abandoned them, whom the boy has become obsessed with, is not his real father. Why do we lie to those closest to us?

Riktor doesn’t like the way the policeman comes straight into the house without knocking. He doesn’t like the arrogant way he observes his home. The policeman doesn’t tell him why he’s there, and Riktor doesn’t ask. Because he knows he’s guilty of a terrible crime. But it turns out that the policeman isn’t looking for a missing person. He is accusing Riktor of something totally unexpected. Riktor doesn’t have a clear conscience, but this is a crime he certainly didn’t commit.

Detective Eira Sjödin is just old enough to remember the summer when 16-year-old Lina Stavred went missing. Her entire community was haunted by the disappearance - especially when Olof Hagström, just 14 himself, confessed to her murder. That was two decades ago. No one in their small rural community has seen or heard from him since, but the spectre of his crime lingers in the forests around the town. But now Olof is back, and he stands accused of another brutal crime.

When young London professional Alex Evans is informed that his sister's body has been pulled from an icy lake in Northern Lapland, he assumes his irresponsible sister accidentally drowned. He travels to the wealthy winter resort where Vicky worked as a tour guide and meets Agatha Koskinen, the detective in charge. Agatha is a no-nonsense single mother of three who already thinks there's more to Vicky's case than meets the eye. As the two form an unlikely alliance, Alex also begins to suspect the small town where his sister lived and died is harbouring secrets. 

Police officer Sebastian Clifford never planned on becoming a private investigator. But when a scandal leads to the disbandment of his London based special squad, he finds himself out of a job. That is, until his cousin calls on him to investigate her husband’s high-profile death, and prove that it wasn’t a suicide. Clifford’s reluctant to get involved, but the more he digs, the more evidence he finds. With his ability to remember everything he's ever seen, he's the perfect person to untangle the layers of deceit.

DI Kate Burrows thought she'd never face a killer like the Grantley Ripper again. But she was wrong. One by one, children are being abandoned. Thankfully, they're rescued from harm. Then one victim is not so lucky, and Kate knows she's in a race against time to save lives. Kate's finding the case tough and she needs the support of her lover, Patrick Kelly, more than ever. But Patrick's got his own problems. A dead body's turned up in his Soho club and, although he insists he's been set-up, Kate begins to doubt him.

Investigator Sofia Kovic has uncovered a connection between several deaths in Oslo over the last year and a half. She tries to call her superior, Alexander Blix, but before Blix has time to return her call, Kovic is shot and killed in her own home. In the apartment below, Blix’s daughter Iselin narrowly escapes becoming the killer’s next victim. Four days later, Blix and online crime journalist Emma Ramm are locked inside an interrogation room, facing the National Criminal Investigation Service. 

On a jagged, bleak lava field just outside Reykjavik stands the Gallows Rock. Once a place of execution, it is now a tourist attraction. Until this morning, when a man was found hanging from it. The nail embedded in his chest proves it wasn't suicide. But when the police go to his flat, a further puzzle awaits: a four-year-old boy has been left there. He doesn't seem to have any link with the victim, his parents cannot be found and his drawings show he witnessed something terrible.