When Sechnussach, High King of Ireland, is found dead in his bedchamber with his throat cut, all clues point to Dubh Duin, the chieftain of the clan Cinel Cairpre. He was found with the murder weapon in his hand when the High Priest's guards entered the royal chamber, before taking his own life. The Chief Brehon of Ireland asks Sister Fidelma to find out what possible motives could have driven Dubh Duin to assassinate the High King. Her investigation 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 . . .