[1] The story moves between two parallel themes – the appearance of a new serial killer terrorizing Oslo, and Harry Hole's ongoing feud with the corrupt and utterly ruthless fellow police officer Tom Waaler, which was already a major part of the plot of the two previous books, "The Redbreast" and "Nemesis".

An emerging pattern suggests that Oslo has a serial killer on its hands, and the five-pointed devil's star seems to be the key to solving the riddle.

Hole, investigating the murder scene, discovers a small, red, five-pointed diamond under the eyelid of the victim and that a finger is missing from her left hand.

A few days later a third victim is found, this time in the female toilets at a law firm, also on the floor and a five-pointed red diamond on the body.

Waaler – who has heard about Hole's suspicions – offers to include him in his illegal dealings, dangling the large financial benefits as an inducement.

The five-pointed diamonds found on the victims are in a similar shape – known as a Devil's Star – and provide a major clue as to the next possible murder locations, which are kept under surveillance: one is in a student residence hall and the other is a house on the outskirts of Oslo, owned by Olaug Sivertsen.

Waaler's argument for the murder is that he would get a lenient punishment from the Norwegian judicial system, and that death would be a worthy sentence for his crimes.

Now a hunted man, Hole's future in the police — and quite possibly his life — depend on his being able to prove Waaler's crimes.

However, a clue is provided by a seemingly irrelevant photograph which Sven shows Hole, and this combined with a very minute but precise piece of forensic evidence points to a completely unexpected perpetrator.

Just as Hole believes that he is in the clear, Waaler calls to inform him that he has kidnapped his surrogate son Oleg and demands that he trade Sven for the boy.