Arthur's enemies are sure a small boy will be easy prey, but they reckon without his guardians. Merlin and Galahad find themselves in a desperate situation when Mordred tries to have them killed and their covert mission fails. Queen Ygraine believes Merlin to be a wizard and offers to help them if they will protect Arthur, her son by the High King. Mordred, however, sees the boy as an obstacle to the throne and seizes the chance to dispose of them all. As the group are hunted relentlessly through the length of the kingdom with a price on their heads, Merlin begins to understand the dangers of their task, and realises that he and Galahad are expendable ... With mercenaries, treacherous barons, and fanatical priests against them, they know they are in a fight to the death. To keep their oath and save the heir to the kingdom they can depend only on their wits, Arthur's loyal attendants Sania and Eris, and Morgana, the woman with strange powers whom they save from a witch's fate. Her friend Wise Woman, who knows many things, also offers unexpected help. And above all they have Merlin's staff and the Galahad factor ...