During excavation work at Glastonbury Abbey in the year 1191, an ancient leaden cross is discovered buried several feet below the ground. Inscribed on it are the wordsHic iacet sepultus inclitus rex arturius:Here lies buried the renowned King Arthur. Beneath the cross are two skeletons. Could these really be the remains of the legendary King Arthur and his queen, Guinevere? As the monks debate the implications of this extraordinary discovery, the bones are spirited away by the mysterious Guardians, a group determined to keep King Arthur's remains safe until the legend is fulfilled and he returns to protect his country in the hour of its greatest need. As the secret of the bones' hiding place is passed from generation to generation, those entrusted to safeguard the king's remains must withstand treachery, theft, blackmail, and murder in order to keep the legend intact.

The Medieval Murderers are Michael Jecks, Susanna Gregory, Bernard Knight, Ian Morson, Philip Gooden, Simon Beaufort, and C.I. Sansom. They are the authors of The Tainted Relic, Sword of Shame, The Lost Prophecies, and House of Shadows.