In the wake of King Uther's sudden death, chaos threatens to engulf Britain. When the sorcerer Merlin has visions of a dark future, he installs the young and impetuous Arthur, Uther's unknown son and heir, who has been raised from birth as a commoner. But Arthur's cold and ambitious half sister Morgan will fight him to the bitter end, summoning unnatural forces to claim the crown in this epic battle for control. These are dark times indeed for the new king, with Guinevere being the only shining light in Arthur's harsh world. Faced with profound moral decisions, and the challenge of uniting a kingdom broken by war and steeped in deception, Arthur will be tested beyond imagination.

Arthur meets Guinevere, the woman of his dreams. Morgan and King Lot conspire to attack Camelot and take the throne. Merlin has Arthur reclaim the legacy sword in the stone to prove his worthiness as king.

Merlin sets off on a journey to find a sword suitable for a king by seeking out a legendary sword maker. A conversation with Guinevere changes Arthur and he begins to assert his power by sparring with Leontes.