Killing Moon

The thirteenth installment in the Harry Hole series finds the former Oslo police detective in self-imposed exile in Los Angeles, broke and drinking himself to death at a neighborhood bar called Creatures. He befriends Lucille Owens, a 72-year-old actress. When armed debt collectors from the Esposito crime family pressure Lucille over a $960,000 debt from a failed movie investment, Harry intervenes and flees with her to a secluded property on Doheny Drive, installing himself as her armed guard.

Meanwhile, in Oslo, Katrine Bratt, head of Crime Squad, responds to the discovery of a woman's body in Østmarka forest. The victim is Susanne Andersen, 26, missing for 17 days, her throat slit and one eye removed. A second woman, Bertine Bertilsen, 27, is also missing. Both attended a rooftop party hosted by Markus Røed, a wealthy real estate mogul, and both had been in sugar-daddy relationships with him. Sung-min Larsen, a detective from Kripos (Norway's national criminal investigation service), joins the case. Katrine lobbies to bring Harry into the investigation, but Chief Superintendent Bodil Melling refuses. At the Forensic Medical Institute, forensic officer Alexandra Sturdza and bioengineer Helge Forfang perform a post-mortem that reveals saliva on Susanne's breast and crude stitches encircling her skull, as though her scalp had been removed and sewn back on. A full autopsy later reveals that someone sawed open the skull and removed her entire brain.

Harry's exile ends when Røed's lawyer, Johan Krohn, tracks him down. Harry initially declines the job, but when Esposito enforcers seize Lucille at gunpoint and give Harry 10 days to pay her debt, he negotiates with Krohn. Røed raises the fee to $1 million, and Harry insists on a clause guaranteeing payment even if the police solve the case within nine days. He catches the next flight to Oslo.

Harry assembles an unconventional team he names the Aune group, headquartered in the hospital room of Ståle Aune, a psychologist and longtime collaborator who has terminal pancreatic cancer. The team includes Truls Berntsen, a suspended officer with access to the police database BL96, and Øystein Eikeland, Harry's childhood friend, who serves as driver and drug-trade insider. Harry reconnects with Katrine, who quietly shares case details. The group's initial analysis points to a psychopathic sexual murderer, though Harry argues for also investigating the victims' acquaintances.

Harry questions Røed using a fake polygraph, catching him in lies about cocaine use but finding no evidence of murder. He visits Helene Røed, Markus's wife, who reveals she is seeking a divorce and possesses undisclosed leverage against Markus. She gives Harry one of Markus's old suits, in whose pockets Harry finds a cat mask and a membership card for Villa Dante, an underground gay club. Sung-min finds Bertine's headless body in Østmarka, confirming the same killer. Near the scene he discovers an empty bag of Hillman Pets, an anti-parasitic powder banned for import in Norway.

Interspersed with the investigation, the narrative follows a character known as Prim. He dines with Bertine's severed head, which he has mounted on a lamp, and tends parasites he keeps in an aquarium. He visits his Uncle Fredric, a former parasitologist who has dementia and who gave him the nickname Prim, after prime numbers, divisible only by one and themselves. Prim eyes a diamond ring for a woman he calls the Woman and contemplates his next victim.

Harry discovers Truls has been leaking information to Dagbladet journalist Terry Våge and shuts down the pipeline. Alexandra's DNA analysis confirms that the saliva on Susanne's breast matches Røed's DNA. When Helene Røed's headless body is found at Snarøya showing extreme violence, Katrine orders Røed's arrest. Harry watches Røed identify his wife's body and break down in tears that seem genuine, deepening Harry's doubts. He infiltrates Villa Dante using Røed's mask and card, posing as Catman. In the club's basement, he corners Filip Kessler, a young cocaine dealer who confirms he was with Catman on both Tuesday nights the first two women were killed, providing Røed an alibi he refused to claim because being outed would destroy him.

The investigation pivots when Prim, revealed to be Røed's former stepson, contacts Våge, proves he is the killer, and directs the journalist to a forest clearing where the heads of Bertine and Helene hang from a birch tree. Prim has framed Kevin Selmer, a street-level cocaine dealer, by planting Selmer's preserved skin between Bertine's teeth and trading him green cocaine laced with lethal parasites. Røed is released, and police arrest Selmer, who dies in his cell hours later from the parasites.

Sung-min discovers that Selmer had a theater ticket proving he was at the National Theater the night Susanne disappeared. The real killer is the person who analyzed the seized green cocaine at the Forensic Medical Institute. That person is Helge Forfang, the bioengineer who has been working alongside Alexandra throughout the case. Aune's hospital roommate, Jibran Sethi, a veterinarian, has explained how the parasite Toxoplasma gondii can be engineered to sexually attract victims to the host, explaining why the women went willingly with their killer.

A frightened Alexandra calls Harry from the roof of the Forensic Medical Institute. Helge takes the phone, introduces himself as Prim, and demands Harry exchange himself for Alexandra. Aune insists on taking Harry's place, arguing it is simple mathematics: exchanging his final painful days for a meaningful death that maximizes the chance of saving the hostage. Wearing Harry's suit, Aune approaches Prim on the roof while Harry follows in hospital scrubs. Prim injects lethal parasites into Aune's neck, believing he has killed Harry. When Harry reveals himself and Prim lunges at Alexandra, she strikes him in the throat using a technique Harry taught her, disabling him long enough for Harry to intervene.

In parallel, Prim has already murdered Røed. He lured his stepfather to the burned-out childhood home in Gaustad, exploiting gondii parasites he slipped into Røed's water days earlier. After recording Røed's confession of years of sexual abuse beginning when Prim was six and programming the video to reach all Røed's contacts, Prim killed him and set the house ablaze. Aune, infected with the fast-acting parasites and already terminal, asks his wife Ingrid to administer a morphine overdose, and she does.

At Aune's funeral, Harry delivers a eulogy honoring his friend's sacrifice. Lucille is found alive in Los Angeles, released after the debt was paid. Katrine offers Harry a permanent position at Crime Squad, but he declines. Helge Forfang has confessed to all the murders; his motive was revenge against his stepfather for years of sexual abuse, with the collateral victims serving as means to sustain his engineered parasites and to frame Røed. The novel closes with a sinister vignette: an unnamed man in a clerical collar, whom Harry has glimpsed repeatedly throughout the story, purchases a chainsaw chain, duct tape, rope, and garbage bags, his soft voice and colorless irises unsettling the store clerk.