The sorcerer Merlin is destined to protect Prince Arthur during his journey to unite the five kingdoms of the earth, and no one knows about Merlin's magic except the court physician Gaius, but what are the threats that Merlin must protect Arthur from?
In season 3, a year after being taken away from Camelot, Morgana is found bruised in the woods and claims to have been kidnapped by bandits, and events quickly begin to unfold.
In season 4, unseen ghosts start to attack the kingdom. In Camelot, Uther has grown weak and has given much of his rule to his deceitful brother-in-law Agravaine, while Merlin realizes what is happening but discovers that his magic insufficient to prevent it.
In Season 5, a search party led by Arthur and Merlin pursues him, a dying priest warns Merlin of Arthur's curse, Ruadan rescues his daughter but is mortally wounded, and Arthur and Merlin make their way to Morgana's winter hideaway.