It is the mid-twelfth century: the Normans have conquered England, Empress Matilda and King Stephen contend for the crown, and continual violence and corruption arise from the sick and vulnerable land. Dame Averilla, infirmaress of the Benedictine abbey at Shaftesbury, is sorely troubled: a precious book of herbal lore has gone missing, and so has Dame Agnes—a nun thought by many to be possessed. And Galiena, rumored to be a witch, has returned to Shaftesbury. Averilla suspects a connection, but her hunger to solve the mystery and restore the abbey to peace is hindered by a disciplinarian sub-prioress and the continuing struggle for power among Norman and Anglo-Saxon women of rank in the wake of the Norman Conquest.