The beguiling Sister Fidelma and Brother Eadulf (her husband) are asked to attend the Council of Autun (a religious conference) in Burgundy, France from their home in Cashel, Co. Tipperary, Ireland in the year 670 AD. They were there on the invitation of a Bishop, who requested them to act as advisors to the Irish Delegates. However, a few days before they arrived two Bishop delegates got into a heated argument that ended up in a brawl.

During the following night, another delegate was murdered, his skull violently smashed in and the two Bishops that were fighting earlier that day, were discovered in the same room, one unconscious with his head covered in blood, the other heavily asleep and his breath smelling of wine. They were immediately put under suspicion.

One of the other Bishops from Ireland, knowing of the previous superb investigative skills of Sister Fidelma and her companion Brother Eadulf asked them to be involved in the murder investigation. At this time celibacy for all religious orders was becoming more common in Europe but it was not so in Ireland (or Hibernia as it was called then), hence Fidelma and Brother Eadulf had to be given special status at the Council, as here it was enforced and all the nuns were kept separate (under lock and key) from the brothers and other religious representatives.

During their investigation Sister Fidelma and Brother Eadulf were involved in many scrapes before the whole plot wound up in a very unexpected denouement. All the characters are well rounded and believable and whilst the two lead characters have our sympathy the other characters are a bit eccentric and unusual. The author mixes historical fact, The Council, with the fiction of the murders, to give more authenticity to his tale.