A serial killer is murdering people around Oslo, taking a finger from each body and leaving a star-shaped diamond. Detective Harry Hole is assigned to work the case with a colleague he despises, Detective Tom Waaler. Harry is convinced Waaler is a dirty cop who murdered Harry's former partner, but he can't prove it. Moreover, Harry's continuual problems with drinking and not showing up for work don't endear him to his superiors, who don't put much credence in his accusations.
The plot is complex and the killer is wily but Harry and Waaler, no matter their differences, work well together. Harry especially uses his usual excellent detective skills (along with some hallucinogenic drugs) to unearth clues and put ideas together. While working the case Harry is (once again) trying to salvage his relatiohship with Rakel, the great love of his life, and to be a father figure to Rakel's son Oleg. Harry's alcoholism and obsession with work keep driving Rakel away and Harry seriously considers taking alternate (though not particularly respectable) employment.
As usual with Nesbo's books, there are plenty of engaging characters, including Harry's police colleagues and friends as well as the suspects, witnesses, and interviewees in the case. Nesbo has a deft hand with characterization and I literally could almost detect a scent when he described some of the more unhygienic characters.
When Harry finally confronts the killer, the perpetrator very obligingly explains his whole motivation and execution - a plan that's so intricate it could only happen in fiction. This put me off a little as I prefer more realistic resolutions to mystery stories. Still, this is a good mystery/thriller with a satisfying resolution.
Highly recommended - you can't go wrong with a Jo Nesbo mystery.