When wisecracking detectives Patrick Kenzie and Angie Gennaro agree to protect the son of a prominent psychiatrist who believes she may have angered the Boston Irish Mafia, they soon find bodies are piling up around them - seemingly unconnected with their case. And what's more all the clues point to an unlikely suspect - a serial killer who has been in prison for twenty years, so he can't be killing again, can he?

As Angie and Patrick try to find out what kind of human being could perform such horrifying acts of rape, mutilation, torture and dismemberment, they discover that the killer's motive is disturbingly rooted in their own distant past. In a series of heart-stopping climaxes that grow ever more terrifying and bloody, the two work frantically with the Boston cops, the FBI, the local Mafia, and the folks from their old neighbourhood to unearth the killer before they become victims themselves.