In the opening of Episode 6 of Jo Nesbø's Detective Hole, Harry finds himself unable to sleep. He reaches out to his drug dealer friend, seeking not only a respite from his insomnia but also assistance in deciphering the serial killer's cryptic messages through pentagrams. The dealer warns him against overdosing and reminds him that the drugs are meant solely for inducing sleep.
Meanwhile, Tom pays a visit to Beate at the forensic lab, scolding her for going over his head and informing Harry about the fingerprint discovery. Beate reveals that she found Willy's faecal matter under Lisbeth's nail, suggesting a possible involvement in her disappearance.
Harry meets with Willy to discuss this revelation. Willy breaks down about his situation, and when Harry mentions the evidence, he explains that Lisbeth had engaged in prostitution with him. Harry tries to comfort him by speaking about his own relationship issues.
Back home, Harry still cannot sleep and leaves a voicemail for Ellen, asking for help with the case. He eventually takes the drug and falls into a deep sleep. In his dream, he hallucinates, feeling trapped and disoriented.
At the same time, Tom calls his superior and announces that he can no longer be part of the weapon trade. Later, he meets the same man at a public washroom and flirts with him, which reminds him of his ex, Lars. The encounter escalates, and Tom suddenly turns violent, killing the man by chopping off his penis in the bathroom. He then leaves the scene and feeds the severed penis to the man's dog waiting outside.
The police begin investigating the murder in the public washroom. Tom tells Møller that it appears to be a homophobic attack targeting a gay man.
Harry wakes up to a call from Rakel, who refuses to join him for Willy's play. She says his job will always come first, and she cannot see a future with him. The scene is filled with tension and drama, leaving the audience on the edge of their seats as they await the next development in this intriguing detective story.
Shortly thereafter, Harry discovers that he has unconsciously carved a pentagram above his bed during his sleep. He also notices the number five drawn on his bedsheet with his own blood, causing him to panic. At the police station, Harry explains that the killer is targeting victims in a pentagram pattern across the city. He maps out the locations of the murders in Oslo and notes that all attacks occur at intervals of five days. He concludes that there will be two more victims and suggests that the killer is targeting women living on the fifth floor. The team narrows down the next target area and begins alerting residents. Harry and Beate visit a middle-aged woman who lives alone, and she agrees to let them stay as a precautionary measure.
Meanwhile, in Prague, a woman tells her partner that she is pregnant. The man is shocked and admits that he has been visiting his mother abroad, insisting that he is not cheating. He opens his suitcase, revealing a gun similar to the one used by the serial killer. Back in Oslo, Vibeke confides in Harry about her troubled sexual relationship with Anders. She says he does not allow her to move or react and asks Harry to be with her, but he declines due to Rakel's presence.
Elsewhere, Oleg leaves Harry a concerning voicemail, and Harry rushes to the swimming pool. He finds Oleg drinking on the diving board. Oleg expresses his desire to understand why Harry and his biological father drink. Harry explains the dangers of alcohol and makes him promise never to drink again. Oleg agrees but asks Harry to fix things with Rakel.
Meanwhile, Tom sets up CCTV cameras around the suspected location of the next attack with Otto's help. Rakel later agrees to meet Harry at the play and asks to speak with him. At the same time, the man from Prague arrives in Oslo while Beate stays with the older woman at her house. The woman shares her past, revealing that she had a child at fifteen and had to send him away. She speaks about wanting to reconnect with her son. Beate grows concerned when she learns that her son, Martin, lives in Prague and is expected to visit that night.
Elsewhere, Tom and Harry monitor the CCTV feeds while the SWAT team detains suspicious individuals. At the same time, Martin kills a man named Marius. Back at the house, the older woman tells Beate that Martin recently gifted her a necklace with a star-shaped diamond. She adds that he has been visiting frequently over the past few weeks. Beate realizes that Martin fits the pattern, confirming her suspicion that he is the serial killer as the episode ends.
