The first season of Detective Hole, based on Jo Nesbø's novel The Devil's Star, concludes with the resolution of two major storylines: the identity of the serial killer and the fate of corrupt officer Tom Waaler.
In a twist, the killer is revealed to be Willy Barli, husband of victim Lisbeth. Harry discovers that seeds under Lisbeth's fingernail came from a café Willy visited on the day of her murder. Willy killed Lisbeth after learning of her affair with Martin Aminov, and staged additional murders to deflect suspicion.
In the final episode, Harry confronts Waaler, who has kidnapped Oleg. During a tense exchange, Harry handcuffs himself to Aminov and lures Waaler into a trap. A struggle ensues, and Waaler's arm is torn off in an elevator. Bleeding out, he dies after a final confrontation with Harry.
The season ends with Harry learning that Waaler may have killed his abusive father as a child. Deputy Chief Agnes Kittelsen asks Harry to return to the police force to root out corrupt officers. Harry finally solves a long-standing bank robbery case, finding closure.
