What Happened in ‘Jo Nesbø’s Detective Hole’s Season 1 Finale? Ending Explained

Netflix’s take on Jo Nesbø’s Detective Hole brings the author’s iconic investigator to the screen: brooding, brilliant, and riddled with flaws. Adapted from the fifth novel in the bestselling series, The Devil’s Star, the story follows Detective Harry Hole as he tracks a calculating serial killer terrorizing Oslo.

Led by Tobias Santelmann and Joel Kinnaman, the series leans fully into Nordic noir, pairing a chilling procedural with a deeper dive into a tragic man whose sharp, obsessive mind is both his greatest asset and his greatest liability. The result is a thriller steeped in atmosphere, examining the cost of chasing darkness without being consumed by it.

Across nine episodes, the first season delivers serial killers, crooked cops, and gruesome crime scenes galore. While Harry Hole investigates a serial killer in Oslo who leaves severed fingers and star-shaped diamonds with victims, he is also at odds with Tom Waaler, a corrupt cop who is targeting Harry. While the finale closes one case, it opens the door to a host of new questions. Here’s a breakdown of Jo Nesbø’s Detective Hole Season 1 ending explained. Warning: Spoilers for Season 1 of Jo Nesbø’s Detective Hole ahead!

Who is the killer in Detective Hole Season 1?

In Episode 9, “Duke Ellington‘s Piano,” Harry (Santelmann) discovers that the killer is Wilhelm “Willy” Barli (Frank Kjosas), a theater producer and the husband of one of the victims, Lisbeth (Dagny Norvoll Sandik).

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Harry confronts Willy at his home, laying out the evidence that ties him to the murders. The key clue comes from Lisbeth’s severed finger, which Willy sent to the police. Forensic analysis reveals fennel seeds covered in fecal matter under her nail, the seeds of which match a meal Willy ate at the Theater Café shortly before her disappearance. Given the digestive timeline, the seeds could only have ended up there after her death, meaning Willy planted the evidence himself by hiding the finger inside his body before sending it in.

Willy confesses. He discovered that Lisbeth had been having an affair with Martin Aminov (Simon J. Berger), a con man selling star-shaped diamonds who targeted wealthy women. Letters between them reveal that Lisbeth viewed her marriage as a convenience and had recently rekindled her relationship with Aminov. Already traumatized by a past betrayal, Willy is pushed over the edge of sanity.

To avoid suspicion, he constructs an elaborate plan: He kills Lisbeth, then creates the persona of a serial killer to mislead the police. He lures Aminov to Oslo under the pretense of a business deal involving star-shaped diamonds, placing him near the crimes to frame him and eliminate any alibi. He even stages messages and sends in Lisbeth’s finger to sell the illusion.

When Harry asks where Lisbeth’s body is, the confrontation turns deadly. Willy reveals she is somewhere “only he could find,” preserving her in his waterbed. As the standoff escalates and Harry braces for the worst, Willy instead leaps to his death from the balcony, choosing to end his story on his own terms.

What happens with Harry’s nemesis, Tom Waaler?

Tom Waaler (Kinnaman), a corrupt cop and longtime adversary of Harry Hole, first tries to lure Harry into joining his illegal arms-smuggling operation. When that fails, he kidnaps his girlfriend Rakel’s (Pia Tjelta) son Oleg (Maxime Baune Bochud) in an effort to force Harry to drop his investigation.

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Using Oleg as leverage, Waaler orchestrates a final confrontation, summoning Harry and Aminov to a student housing building with a plan to frame Harry for both kidnapping and murder. He handcuffs them together to set the scheme in motion, but Harry anticipates the setup, swallowing the cuff key and using the building’s surveillance to undermine Waaler’s plan.

A violent struggle erupts in an elevator as Harry, Aminov, and Waaler fight for control. In the chaos, Harry turns the tables, ultimately cuffing himself to Waaler after tricking him by swallowing a different key. With Waaler’s arm stuck in the elevator window, the descending lift severs his arm. Badly wounded but still dangerous, Waaler attempts one final ambush, but he succumbs to his injuries, dying from blood loss before he can finish the job.

How does Detective Hole Season 1 end?

Oleg is safely returned to Rakel, and Harry is welcomed back into their lives, promising to stay in touch.

Martin Aminov is placed back in custody, while Chief Viktor Møller reviews the student housing surveillance footage alongside statements from Aminov and Oleg — evidence that ultimately clears Harry. He will not be prosecuted for Tom Waaler’s death.

Still wary, Harry calls reporter Maya (Kelly Gale), who warns that her phone may be bugged. She admits she thwarted his attempts to bring notice to Tom’s illegal activity after threats were made against her brother. Harry gives her a way to make things right: He’ll provide a story exposing everything — but only if something happens to him or the people he loves.

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Harry meets with Chief Superintendent Agnes Sjolid (Agnes Kittelsen), who tells him she won’t dismiss him. There are other “rotten apples” in the police force beyond Tom, and she needs his help to find them. But to do that, Harry would have to stay quiet about Tom’s weapons smuggling operation. When Sjolid asks if Tom had any partners, Harry says not that he knows of.

Also, Willy Barli’s murder of his wife and his creation of a serial killer persona to divert suspicion, knowing it’s “always the husband,” helps Harry and his colleague Beate (Ellen Helinder) crack a cold case from five years earlier. In that case, a bank teller was killed during a robbery, but they realized the truth: Her husband was the killer, and the robbery was simply a distraction.

How does the Detective Hole finale set up Season 2?

After the seemingly happy ending, viewers are taken to a mysterious room covered in lavish murals, where figures in tuxedos and black masks gather to discuss their next move.

“What do we do now?” one asks.

“It’s simple. We regroup and lay low for now,” replies the leader. She then removes her mask, revealing herself to be Sjolid. “After that, we come back stronger,” setting up a possible story for Season 2.

Jo Nesbø’s Detective Hole, Now streaming, Netflix