In little more than a year, Inspector John Rebus will retire. Shuttled off to the sidelines by his superiors, he watches as his colleagues are recruited for security. The G8 Conference of world leaders is descending on Scotland. When his old partner and now superior, Siobhan, calls him regarding a possible serial killer operating in the area, Rebus jumps at the chance to investigate. It seems the victims are recently released paroled rapists. When he discovers that the employer of one victim is his long-time nemesis, Cafferty, a gangster who operates a large criminal operation, Rebus believes he has one more chance to nail Cafferty.

As the G8 Conference begins, one of the participants is found dead at the base of Edinburgh Castle. Was it murder or suicide? And did it have any relationship to the other killings? The government and secret service refuse to cooperate with Rebus' investigation, throwing obstacles every inch of his way. In order to solve the crime, Rebus must make an uneasy alliance with the devil.

Rankin gives added texture to the mystery by using the backdrop of the G8 Conference with its real-life characters and incidents from the controversial political event. He sprinkles songs and musicians throughout the tale enriching it further. There are plenty of twists and surprises, leaving Rebus and Siobhan with an uneasy future with their superiors and Cafferty.