In 1195, Prince John and Philip II of France support a scheme to finance rebellion against Richard I through an alchemist who claims he can turn base metal into gold. The vessel carrying Nizam and his companions toward the Devon tin country is wrecked, and its crew is found slaughtered.
Soon afterwards a Norman knight is crucified, beheaded and displayed inside Exeter Cathedral. John searches for the connection between the ship, the murder and the promised gold, while disgraced former sheriff Richard de Revelle attempts to conceal his role in a conspiracy that reaches from Devon to the rival courts of England and France.