S4, E12: With Morgana at the helm of a vast Southron army, a deadly net is closing in around Camelot... When the sorceress strikes, the ferocity of her attack forces everyone to run for their lives - even Arthur. But Morgana won't let him escape that easily. And so begins a chilling hunt... Can Merlin save the King from Morgana's clutches? Or has Arthur's luck finally run out?