Ireland, AD 671. King Colgu of Cashel is shocked to learn that his loyal Chief Bishop and advisor has been murdered in the old enemy fortress of the Ui Fidgente. When word reaches Cashel that the culprit will be executed under new law, a larger conflict threatens. Dispatched to investigate, Sister Fidelma and her companion Eadulf discover that the man facing punishment is Gorman - commander of the King's bodyguard. But Fidelma cannot believe Gorman would carry out such an act - and yet he was found locked in a chamber with the body, weapon in hand. The evidence is stacked against him. If they are to save Gorman and keep the peace between the kingdoms, Fidelma and Eadulf must find the true culprit. As the threat of war looms, the date of execution drawers ever closer.