November 1214. King John has returned to England having lost his empire to King Philip of France. Humiliated and desperate for support, he again travels to Bury St Edmunds where Abbot Samson has died and a battle is raging among the monks over who will be his successor. In the midst of this there arrives in the town a seemingly inconsequential young couple and their maid. The wife is heavily pregnant and gives birth in the night to a baby daughter. But then the maid is mysteriously murdered and it is soon apparent that the family is not all that it appears. With rebellion looming, abbey physician Walter of Ixworth is drawn once again into investigating a murder and a conspiracy that threatens to engulf the country in civil war and ultimately leads to the final nemesis that is Runnymede and Magna Carta.