The corpse of local teenager Angela Cashell is found on the Tyrone-Donegal border, between the North and South of Ireland, in an area known as the Borderlands. Garda Inspector Benedict Devlin heads the investigation. The only clues are a gold ring placed on the girls finger and an old photograph, left where she died. While Devlin searches for the girls killer, her father has his own ideas about who is responsible; and his own ideas about how to make them pay. Meanwhile, Devlin becomes reacquainted with an old flame eager to rekindle their affair. Then another teenager is murdered, and Devlin unearths a link between the recent killings and the disappearance of a prostitute, twenty-five years earlier; a case in which he fears one of his own colleagues is implicated. As a thickening snow-storm blurs the border between North and South, Devlin finds the distinction between right and wrong, vengeance and justice, and even police-officer and criminal becoming equally unclear.