Oxford, 1374: At the command of the Lord of the Isles, Muirteach and his wife Mariota accompany Donald, the lord's surly thirteen-year-old son, to Oxford. Shortly after their arrival a winsome tavern maid disappears. Muirteach attempts to help Undersheriff Grymbaud with the investigation, as well as keep Donald at his studies and out of the taverns. He has little success with either venture. Mariota thirsts to attend medical lectures at the schools and seeks a way to gain admittance to these classes. An Oxford master is brutally bludgeoned to death, and Grymbaud asks Muirteach to investigate the slaying. The arrest of an aged servant for the murder stirs the ever-simmering discord between townsfolk and university students. Then Mariota vanishes. Gleaning clues from a cryptic manuscript and desperate to save his wife, a determined Muirteach tracks a wily killer through a dark and twisted labyrinth of deceit.