In November of A.D. 667, Fidelma of Cashel - sister to one of the kings of Ireland, a religieuse of the Celtic Church, and an advocate of the Brehon courts - returns home to her brother's castle to find herself facing a mother's nightmare. A servant, her son's nurse, was found dead, brutally murdered, in the woods near town, and Fidelma's child, who was with the nurse, is missing, presumed kidnapped or worse.

Sister Fidelma and her husband, Brother Eadulf, must gather their strength and bring their wits to bear on their most personal and baffling case ever. Is there a traitor at her brother's court? Are the Ui Fidgente, the old blood enemies of Fidelma's royal family, using her son in a scheme for revenge and power? And what is the role of the mysterious dwarf seen leaving the kingdom carrying a leper's bell? With few clues and precious little time, Fidelma must unravel the threads of this complicated puzzle if she is able to recover her missing child in time.