When Sechnussach, High King of Ireland, is found dead in his bedchamber with his throat cut, all clues seem to suggest an all-too-obvious prime suspect. Dubh Duin, the chieftain of the clan Cin l Cairpre, was found with the murder weapon in his hand when the High King's guards entered the royal chamber, before taking his own life. The Chief Brehon of Ireland asks Sister Fidelma to investigate and find out what possible motives could have driven Dubh Duin to assassinate the High King. Her investigations reveals an intricate web of conspiracy and deception that threatens to unbalance the five kingdoms and send them spiralling into a violent and bloody civil war and religious conflict...