When Merlin falls into Morgana's hands, he becomes a deadly weapon in her fight for supremacy. Using ancient magic and a serpent-like creature called a Fomorroh, she pits friend against friend to create the perfect assassin.
Fortunately, Merlin's many attempts to put an end to Arthur fail, and Gaius and Gwen work to remove the Fomorrah...or so it would seem. But just when it seems Merlin is cured, another Fomorrah appears, leading to the conclusion that the mother beast must be killed. Gaius paralyzes Merlin's Fomorrah, and the young wizard transforms himself into the elderly Dragoon in order to carry out his mission.
After a battle of sorcery with Morgana, Merlin emerges victorious and is able to destroy the mother Fomorrah. Gaius can now heal his ward, and Merlin can return to his duties as Arthur's servant...after some playful chiding from the King, of course.
Merlin has pushed the limits of his strength to save Arthur, but even he may not be powerful enough to rescue Camelot€™s king.
In the battle foretold by the prophecies, all give their best, and Merlin wins the day.
Morgana may have one last trick up her sleeve to win the war.