Ordered by Henry II to establish the possible role of Eleanor of Aquitaine in the poisoning death of Henry's mistress, a reluctant Adelia Aguilar joins forces with her infant daughter's father, the Bishop of St. Albans, during an investigation within the labyrinth-walled tower of the victim's home.

When the bodies of two people are discovered in the remains of an arson fire that destroyed Glastonbury Abbey, Adelia Aguilar, Mistress of the Art of Death, is ordered by Henry II to determine if one of the sets of bones belongs to the legendary Celtic savior Arthur.

Sent to medieval Cambridge in order to exonerate Jewish prisoners who have been accused of murdering four children, University of Salerno medical expert Adelia discovers that the killer may be a former crusader.