Fast forward a dozen years and the "Little Redeemer" - now a hitman for hire - goes to Norway and kills Robert Karlsen, a respected young member of the Norwegian Salvation Army. The hitman soon discovers he mistakenly assassinated the wrong guy. He then goes after Robert's brother Jon Karlsen, the true target. Enter Inspector Harry Hole and his team of detectives, whose job it is to capture the murderer and prevent further deaths. A great deal of the book involves the hitman chasing Jon Karlsen and Hole's team chasing the killer.
Much happens along the way: the killer demonstrates clever skills in escaping the cops and hiding out; Hole travels to Croatia; a police officer is stabbed; a woman is murdered in a horrifying way; another girl is raped, and much more.
Of course there are plenty of side issues: Robert Karlsen has a reputation for liking young girls and seems to have gotten friendly with a 15-year-old Croation refugee. Jon Karlsen has a girlfriend but is also involved with a married woman whose husband wants to purchase Salvation Army properties. Hole develops a relationship with the pretty Salvation Army worker, Martine, who was raped at the beginning of the book. And there are lots more interesting characters who interact in a variety of ways.
Jo Nesbo loves to include lots of misdirection and unexpected twists in his books, and he outdoes himself here. The book is chock full of surprises. This is a complex,engaging story. A good mystery thriller.