Morgana takes the dying Morgause to the Isle of the Blessed where she unwittingly tears the veil to the spirit world, unleashing the Dorocha, invisible ghosts that begin to attack the kingdom. At Camelot, where a weakened Uther has given over much of his rule to his scheming brother Agravaine, Merlin senses what is happening but finds his magic inadequate to stop it. As Camelot fills with refugees, Gaius reasons that, as one death opened the portal, only another will close it. Arthur offers himself as the sacrifice and travels to the Isle of the Blessed with Merlin …
Watch It Here : Merlin Season 4 Episode 1
