Assuming you’re up to speed from last time, let’s rejoin events at the battle of Camlann.
Merlin makes his way to Arthur, where the knights are becoming swamped by Saxon warriors, including Mordred with his magical sword, Morgana strafes them with dragonfire, and blows away anyone that threatens her champion. It’s going to take a miracle to save Arthur’s men.
A miracle, or some heavy-duty magic, from Emrys (the old Merlin that emerged from the Crystal Cave). He blows away the Saxons with force and lightning, knocks Morgana over, and drives her dragon away. Arthur’s men charge, routing the Saxon army and forcing them to retreat.
However, Mordred has not been so easily driven back. As Arthur rushes to help a fallen knight, he approaches from behind. Arthur rises to defend himself, and Mordred stabs him with his sword. He gets one back in his own belly for his trouble, and dies. Not that this helps Arthur, who collapses, lost in the battlefield, while his knights and Gwen search for him.
Emrys finds Arthur, and gathers the king up for the long walk back through a valley of dead knights. When Arthur comes to, Merlin, who is young Merlin again, has made a camp for the two of them, and while Arthur is laid up with his wound, Merlin tells him that he is a sorcerer, the sorcerer, in fact, that beat the Saxons.
At first, Arthur is unsure, but Merlin gives him a little magical show to convince him. But rather than accept his friend’s talents, Arthur asks Merlin to leave him.
Gaius attends to the kings wound while Merlin looks on, upset, as his former friend and employer refuses to acknowledge him. There’s a fragment of Mordred’s sword stuck in Arthur’s chest, and working its way towards his heart. The best solution seems to be the Sidhe, of the lake of Avalon. Merlin resolves to take Arthur, and Gaius goes back to Camelot to explain what’s what, with the Royal Seal in his hands for Guinevere.
Meanwhile, Morgana buries Mordred, and swears she will have her revenge yet. Her men are searching for Arthur too. Or at least, the ones she hasn’t killed out of frustration are.
Merlin defends Arthur against two Saxon soldiers, using magic, and again, his only reward is a barbed comment from his king. It seems forgiveness is going to be a little slow in coming.
Treacherous Eira has been uncovered, after sending a note to Morgana that sends her in the wrong direction, and executed, on Gwen’s orders. Gwaine is understandably furious that the woman who saved his life has betrayed him, and sets out with Percival to find Morgana and punish her.
Arthur and Merlin share a tender moment, as they often do just before sleep. Maybe forgiveness is closer than it seems. And Gwen works out who Merlin really is, and is glad of it. Although everything hangs in the balance, maybe it’s going to be alright after all?
Gwaine and Percival lay an ambush for Morgana and her men, but she defeats them, and they are captured. Morgana tortures Gwaine with a Nathair, while Percival struggles against his ropes (eventually snapping them with his mighty strength). A guilt-ridden Gwaine confesses that he has failed, and that Morgana knows the secret of Arthur’s location, before dying in Percival’s muscly arms.
It’s not far to the lake now, but Morgana is on her way. Arthur finally forgives Merlin, and apologises for treating him badly, and just as they’re about to set off for their final journey, Morgana arrives. She drives Merlin and Arthur’s horses away, and blasts Merlin out of the way. As she gloats over Arthur’s prone form, Merlin approaches with Excalibur. She claims to be immune from any mortal blade, but this is not that kind of sword. He stabs her, and she dies. Now there’s only the small matter of getting Arthur to the lake.
Except they don’t really have enough time. Arthur knows his time has come, and insists that Merlin just hold him, because he has something to say: thank you.
And then he dies.
Merlin, howling at the skies, calls Kilgharrah, to bear them over to the lake. At the shore, the dragon tells him there is nothing he can do to save his friend, but that Arthur, the once and future king, will rise again when Albion’s need is greatest.
And, finally accepting the situation, Merlin throws Excalibur into the lake, where the sword is caught by the Lady of the Lake. He then places Arthur’s body in a boat, and, sobbing, he sends the boat onto the lake, bearing his lifeless friend out across the water, and off into legend.
And that’s that. That’s the end of the story. Gwen is now queen, Arthur is lost to legend, and an old man called Emerys patrols the shore of Lake Avalon – even into modern times – waiting to see his friend rise one more time.