Episode 3 of The Chestnut Man: Hide and Seek Season 2 opens with Le's delight at seeing Mark staying over despite the stalker's threats. Naia is hesitant to inform Esra and promises to keep a worried Mark informed of any updates.
The investigation unfolds with the revelation that both Zara and Andreas cheated on their spouses, but Emma did not. The presence of multiple blows, stabs, and bruises suggests that Emma knew her killer and the crime was personal. Sandra also discovers three similar stalker complaints: Ali fled the country, Berit stopped being stalked after reuniting with her husband, and Ditte is in hiding, having an affair and going through a divorce from her violent ex-husband. The police learn that Ditte, Zara, and Andreas turned to the Agency for Family Law for their divorces.
Signe, a widow from the grief support group and a friend, checks on Marie. Marie feels guilty for often arguing with Emma and being unaware of what was happening. Signe advises her to move on for the sake of her remaining children. Gradually, Signe helps Marie clean out Emma's room.
The hospital attempts to wake Jon. Naia suggests Mark visit his brother, but he insists on staying by her side. He receives a selfie from Le with the pet canary, which upsets Naia. She warns him not to string Le along. Back to the case, the agency's deputy director introduces the police to Ditte's caseworker, Ole. Ditte plans to show up for the custody battle verdict.
Marie ends class early and spots Emma's friends. She checks in with them, and Silje accidentally mentions their group's list of people they fantasize sleeping with, which includes teachers. Next, the police question Peter, Ditte's ex-husband and her current girlfriend Lena, but they know nothing. Aksel digs up the 1992 case of a paedophile playing hide-and-seek with his victims. Three children were killed, and the third was found in the marshlands. The police get a lead when Ole recalls Ditte living with a colleague. Peter follows Naia and Mark as they head there.
Ditte is getting ready to head out for the meeting when she receives the first countdown text from the stalker. She panics but Mark shows up.
Marie observes Silje engaged in a lively conversation with Bo, the youthful and energetic teacher who stands by her side. Suspicions creeping in, Marie delves through Emma's assignments and discovers some belonging to Bo's class. One paper, titled 'erotic obsession,' bears romantic notes in the margins. Ditte confides to the police that Peter is controlling, mentally unstable, and perfectly capable of being the stalker. The stalking began after the summer break, when he first reached out to her through the agency. The police also uncover "cuckoo" texts from the stalker when Ditte went underground, as if he were searching for her. The police ponder if the stalker could indeed be Peter.
In the meantime, Marie confronts Bo, who was a chaperone at the party where Emma went missing, publicly. Thor and Principal Anders believe she needs help and refrain from investigating Bo further. The police return to question Peter and find his house empty. Jon awakens, and Naia convinces Mark to be by his brother's side. Jon is surprised that Mark returned for him and claims to be proud of him despite their tumultuous upbringing. However, Mark insists that there's a price to pay. As for Naia, she delves into Peter's computer and discovers gruesome Photoshopped pictures, blaming Ditte for their family's ruin.
Meanwhile, Peter follows Ditte to the agency. Confused, he calls his lawyer and is enraged to learn that he will likely receive monthly visitation rights. He attempts to barge in but when refused, he shoots the receptionist. He terrorizes the agency with his rifle as he searches for Ditte.
Having considered Jon's words, Mark invites Naia out for dinner on the spur of the moment. She is elated but hangs up upon reaching the agency and witnessing the chaos. Peter kills Ditte's police escort and Ole. Naia attempts to negotiate with him but he shoots her and flees with Ditte. Naia tries to pursue them before collapsing.
When Mark arrives, the police have already taken over the crime scene. He is horrified to see Naia's lifeless body.
