January, 814 A.D. Charlemagne lies dying in his palace, and the life of the mighty Carolingian Empire hangs in the balance. Everything could be lost.Emperor Charles's eldest son Louis was anointed to preserve the empire and ensure peace after his father's death. A prophecy tells of Jesus's crown of thorns: whoever possesses the crown rules the world by divine right-and Charles has struck a fragile truce with the Emirate of Córdoba for the crown's delivery.But rivals to the throne have machinations of their own, and the crown never arrives in Aachen. Charles the Great dies before his son ever sees the holy relic, and the quest to claim the empty throne begins.