A storm drives Fidelma and Eadulf's ship onto the coast of the Welsh kingdom of Dyfed while they are travelling towards Canterbury. King Gwlyddien and Abbot Tryffin ask them to investigate the disappearance of an entire monastic community, including the king's eldest son, from an isolated settlement. A local woman's murder suggests that the vanished monks did not simply abandon their home.
The investigation takes Fidelma through a region divided by political loyalties and distrustful of Eadulf's Saxon origins. She must connect the empty monastery, local violence and the interests of neighbouring rulers before the missing community becomes the cause of a wider confrontation.