The Heretic's Apprentice — Ellis Peters

In the summer of 1143, William of Lythwood returns to Shrewsbury in a coffin ... his pilgrimage at last at an end. William's young attendant, Elave, accompanies the body and sets about trying to secure a burial place on the grounds of the Abbey of Saint Peter and Saint Paul, despite William's once having been reproved for "heretical views."

Elave, too, has evidently learned skepticism. After he drunkenly expresses heretical opinions, the mighty prelate Gerbert brings capital charges against him. The beautiful Fortunata, whom Elave adores, becomes a reluctant witness for the prosecution.

When violent death follows, Brother Cadfael is once again called from his herbiary to aid his old friend Hugh Beringar, the sheriff. Cadfael's new task is twofold -- there are charges of heresy to be rebutted as well as a murder to be solved...