The Leopard starts with a Norwegian police officer arriving in Hong Kong to retrieve our battered hero. There is a serial killer on the loose in Norway, and Harry is only person the Norwegian police think can solve it. Harry, however, is very, very reluctant to take on the case. He seems content to finish the job of destroying himself with opium and horse racing on the other side of the world. Because this would be a very short book otherwise, Kaja Solness convinces Harry to come back to Norway, if only to say goodbye to his father.
Once back on his old stomping ground, Harry can't resist picking up the case. For a miracle, he also manages to avoid going on any benders. Nesbø's books are full of twists and here's the first one. Harry's Crime Squad is competing against the national Kripos for the right to investigate murders. The Kripos, under the odious Bellman, have managed to make a convincing case to the Ministry of Justice. For now, all murders are their turf. Harry and his minuscule team (one detective and one forensics expert) have to investigate on the quiet to that the Kripos don't find out about it.
With all this hovering over him, Harry has to work on puzzling out a bizarre series of murders. The killer is a serial killer, but only in the strictest sense. There's no ritual, none of the other hallmarks of serial murder. The victims are not selected because of who they represent, but because they might have witness something. They're murdered with different methods. There's no timeline. And then the twists start. I think Nesbø has outdone himself with this one. The plot is utterly fantastic, but so well written that you have to believe it.
Even if the rest of the book weren't up to par (and it's well above), the ending would be worth sticking around for. The climax of the book takes place in Goma, Congo and partly on the sides of Mount Nyiragongo, a deadly volcano. The ending of this book is terrifying. The book up to this point has shown you that the killer is capable of extraordinarily sadism against his victims. Nesbø keeps tension going right up until the resolution. Since he's killed off supporting characters before, there's no guarantee that it's going to be okay this time.
And on that note...I'm going to stop talking about the plot. The Leopard is a mystery; you're going to have to read it for yourself if you want to know what happens.
Thematically, the thing that struck me about this book was manipulative people can be. Everyone wants something in this book and most of them aren't afraid to wheel and deal or hurt people to get them. Bellman wants to be at the top of the heap and will blackmail or threaten anyone to get it. The killer wants revenge. Harry's boss wants to preserve the status quo. Kaja wants love. And Harry, I think Harry wants redemption. He just has no idea how to get it and how to stop blaming himself for his failures. This is other thing I like about Nesbø's books. You get a terrific mystery, sure, but you also get deep, carefully drawn characters. If you can handle the gore, these books are excellent.