As Arthur Pendragon, the once and future King, lies dying in Merlin's arms, the Great Dragon makes a promise. "One day, when Albion's need is greatest, Arthur will rise again." And so he will. Time has passed since the Kings death but the newly formed Kingdom of Albion is struggling without him. For a new threat has arisen. More powerful than Morgana ever was. Without Arthur's help, Albion will surely fall. And so, as always when he is needed, Arthur returns to do what he does best. Fight for what he loves. A long and difficult journey begins in the world of the BBC series "Merlin".