In the wake of King Uther's sudden passing, 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.

Arthur is crowned King of the Britons and Morgan and Lot have a falling out. Morgan decides to turn to other "dark" methods of gaining what she wants even at a price.

Kay and Leontes seek out a trusted new warrior to join them. Arthur and Merlin accept an invitation to join Morgan at her castle for dinner. Arthur is forced to concede defeat in his pursuit of Guinevere.

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.

Arthur creates Camelot's first tribunal of justice which is created through battle of wills. Morgan is helped by Sybil to reach out to the people of the town on her quest to take back the throne.

The men of Camelot discover the territory beyond the castle is filled with danger and disorder. Arthur hears Guinevere has ridden out alone to see her father and goes after her to protect her on the journey.

Morgan puts on a feast for King Arthur and his Knights at Castle Pendragon which turns to panic as the castle comes under attack. As Arthur and Morgan's men join forces to fight, Merlin believes a plan is afoot.

Pursuing the power of her dark magic, Morgan hides in plain sight at Camelot where she begins her plan to drive a wedge between Arthur and his men. Igraine tries to find a way out of Castle Pendragon.

Bardon Pass is attacked and Arthur and his men rush to protect it. Merlin discovers Morgan has been in the castle all this time.

The battle of Bardon Pass continues as Arthur tries to defend it alone. Meanwhile Morgan continues with her plan to take the throne while Arthur is away.