A young nun is found violated and murdered, while the brother and sister she was escorting have disappeared. A mysterious forest ranger dedicates himself to rescuing the children, while Brother Oswin blames himself for Sister Hilaria's death. Cadfael must identify the killer and do what he can to aid in the children's rescue.
Cadfael is sure the unlikely novice Meriet is hiding a secret, and when a missing bishop's envoy is found dead, Meriet takes the blame. Cadfael must discover who Meriet is protecting and who is the real murderer. Ellis Peters fans will find the character name changes confusing and not helpful to the story.