When Bishop Leodegar of Autun calls upon the church leaders from western Europe to attend a council, it is to be a meeting haunted by sudden death and intrigue. It's AD 670, and the Council of Autun is meeting to discuss serving a final devastating blow to the Celtic Church. But when a conflict between two delegates results in the murder of the chief delegate from Hibernia, the entire Council is in danger. Sister Fidelma and her companion, Brother Eadulf arrive in Autun to act as advisors to the Irish delegation. Between the autocratic Bishop Leodegar and the malignant abbess, Mother Audofleda, a web of sinister intrigue spreads and soon includes the theft of a priceless reliquary box, the disappearance of women and children and rumours of a slave trade...