Swords, sorcery and swashbuckling adventure return in the third series of Merlin, following our heroes as they face their greatest challenge yet. When misbegotten secrets are exposed and old friends choose new sides, they soon discover that the great battle for Camelot is only just beginning...

Merlin is bac for a fourth series, with Camelot standing on the brink of a golden age. But its birth will not be an easy one, for the forces of evil are gathering and the darkest hour is just before the dawn...