In the summer of 1311, a jousting tournament is about to commence in the Tower of London, supervised by Sir Hugh Corbett, Keeper of the Secret Seal.
Two powerful lords have come forward with writs from the late king, promising them both the inheritance of a lucrative estate. To settle the dispute, they are submitting their quarrel to the judicium Dei: the Judgement of God. But when a third claimant comes forward, Corbett suspects that something is awry.
Corbett launches an investigation to uphold the reputation of the late king as treachery looks set to spread. But it soon becomes clear that more than one person in the Tower has secrets to keep...