Morgana sends a carrier to Camelot with a giant slug, which attacks Merlin and robs him of his magic. As Morgana and Mordred prepare their onslaught on the kingdom, Arthur leads an army out to meet them, but Merlin travels to the Crystal Cave where, inspired by an apparition of his father, he regains his powers and, in his guise as an old man, hurries to meet Arthur and join battle.
Watch It Here : Merlin Season 5 Episode 12
