Part 1 Merlin, an elderly man telling his life story, describes a
Britain faced with
invasions and tyrant kings increasingly cruel to the people. King Constant, the first Christian King of
England, is executed by
Vortigern, who immediately takes the crown and proclaims himself king. Fey goddess,
Queen Mab, seeks to reclaim her power by drawing people back to worship
The Old Ways. To do so, she creates a wizard named Merlin, whom she intends to champion her crusade. Merlin's mother dies giving birth to him, and he is raised by his aunt, Ambrosia, who left the Old Ways and has since converted to Christianity. Now a teenager, Merlin recounts to Ambrosia how he rescued a nobleman's daughter, Nimue, from drowning by magically growing a branch. Ambrosia tells him of his past, and he is sent to Mab to begin training with Frik, Mab's gnome servant. Despite great aptitude, however, Merlin has little interest in helping Mab's crusade to restore the Old Ways, infuriating her. Merlin discovers from the
Lady of the Lake, Mab's sister, that Mab let his birth mother die and that Ambrosia is terminally ill. Mab reaches Ambrosia's home before Merlin, but when Ambrosia refuses to convince Merlin to return to Mab, Mab lashes out, mortally injuring Ambrosia. Enraged, Merlin tries to attack Mab but can't defeat her. She coldly dismisses the deaths of his mother and Ambrosia as "casualties of war" and vows that Merlin will help her. Merlin makes a blood oath to use his powers only to defeat Mab. Many years later, King Vortigern is unable to trust even his closest allies, including Nimue's father Lord Ardent. Paranoid that Ardent will defect to
Uther Pendragon, King Constant's son and heir to the throne, Vortigern has Nimue imprisoned, threatening to have her executed if Ardent betrays him. Wanting to keep Nimue safe, Ardent begrudgingly agrees. Angered that his new castle keeps collapsing, Mab convinces Vortigern his castle will only stand if Merlin's blood is mixed with the mortar. After the Soothsayer asks Mab for guidance, she orders him to find Merlin and bring him to Vortigern. Merlin is captured by the king's guards, Vortigern orders the Soothsayer to kill him, but relents when Merlin tells Vortigern of his vision: a
red dragon representing Uther defeating the
white dragon that represents Vortigern. Mab persuades the king that he can defeat Uther by sacrificing Nimue to a dragon in the hope that Merlin will break his vow not to use magic. Vortigern is reluctant due to his agreement with Ardent. Frik, disguised as one of Vortigern's guards, falsely claims that Ardent has defected to Uther. Convinced of Ardent's betrayal, Vortigern agrees to Mab's deal and the two become allies. Merlin uses magic to untie himself from a tree and save Nimue, but not before the dragon badly burns her. Merlin brings Nimue to
Avalon to recover from her burns. Merlin asks the Lady of the Lake for help, and she gives him the magical sword
Excalibur. Merlin warns Uther of Vortigern's intention to attack him in winter instead of spring. Heeding his warning, Uther agrees to meet Vortigern at the battlefield. During the battle, Vortigern kills Ardent and Merlin uses Excalibur to break the ice, causing Vortigern to drown in the freezing water. Afterwards, Merlin gives Excalibur to Uther and he is crowned king. During a feast celebrating Uther's victory, Mab uses her magic to make Uther become obsessed with
Igraine, the wife of
Gorlois, Lord of
Cornwall. Seeing his emerging madness, Merlin tricks Uther out of Excalibur and plunges it into the Rock of Ages, who promises to keep it until a good man can withdraw it. Uther's mind is plagued by lust for Igraine, and Britain slides back into civil war. Merlin strikes a deal with Uther to let him seduce Igraine in exchange for guardianship of the son born from the union and for Gorlois and his men to be spared. Merlin transforms Uther's appearance into that of Gorlois, fooling everyone in
Tintagel Castle except for Igraine's young daughter,
Morgan le Fay. After seducing Igraine, Uther has Gorlois and his men slaughtered, deliberately going back on his word to Merlin. Nine months later, Igraine goes into labor, while Frik, at Mab's behest, convinces Morgan to place a black stone beneath the baby's sheets in his crib. Igraine gives birth to
Arthur much to Merlin's relief. Mab confronts Merlin, proclaiming Arthur to be damned, but Merlin vows to raise him in the ways of good and hopes Arthur will help bring about her demise.
Part 2 Merlin begins tutoring Arthur. Meanwhile, Uther sinks further into madness and commits suicide, leaving the kingdom in turmoil. The noblemen in the kingdom try to take Excalibur from the Rock of Ages, but none can until Merlin presents Arthur, who is allowed to take the sword. After initial hostility, the nobles unite behind Arthur as their rightful king. Merlin leaves, thinking the kingdom is finally at peace. Mab, however, instructs Frik to seek out Morgan and poison her mind by making her beautiful and having her seduce Arthur, who is unaware of their half-sibling relationship. Merlin races back to Camelot to confront Arthur and Morgan gives birth to
Mordred, who, conceived through incest, is born evil. Mab helps raise Mordred as her protégé to defeat Arthur and claim the throne for himself. Meanwhile, Morgan, entranced by Frik's magic tricks, has fallen in love with him. Arthur begins construction of his castle of Camelot and marries
Guinevere. Arthur decides to take his knights on a quest for the
Holy Grail. He holds a tournament to crown a champion who will defend and complete Camelot in his absence. The Lady of the Lake vows to guide Merlin to a man worthy of being Camelot's guardian. Merlin meets a boy,
Galahad, and his parents,
Lancelot, a skilled rider and swordsman, and
Elaine of Corbenic. Merlin brings Lancelot to Camelot, where he wins the tournament. In Arthur's absence, Guinevere and Lancelot embark on a love affair. Mab makes sure Elaine sees his betrayal, and she is found dead at the shores of Camelot not long after. Lancelot apologizes to Guinevere and flees Camelot in his guilt and shame. Arthur and his knights return, their quest for the Grail a failure. Mordred introduces himself as Arthur's son and heir and reveals Guinevere's betrayal to everyone. Arthur, who still loves Guinevere despite her infidelity, is forced to condemn her to be burned at the stake for treason, but he relents and has Merlin save her before she is harmed, causing him to lose respect among the younger nobles. Lancelot rides back to Camelot to save Guinevere, and they ride away into exile. Mordred raises an army among those dissatisfied with Arthur and Merlin. When Morgan refuses to allow Mab to use Mordred further, Mab kills her. Frik turns against Mab and vows revenge on her, but is left powerless when she takes away his magic. Mab creates an idyllic wilderness home for Nimue and asks her to persuade Merlin to stay with her, hoping to stop him from intervening in the coming battle. Wanting to be with him, Nimue agrees and sends for Merlin. The armies of Mordred and Arthur begin the
Battle of Camlann, where many on both sides are slain. Arthur defeats Mordred and kills him, but Mordred deals Arthur a fatal blow. Sensing his protégé is dying, Merlin leaves Nimue to go to Arthur, but Mab's creation seals itself behind him, separating Merlin from Nimue forever. On the battlefield, Mab mourns Mordred, and Arthur tells Merlin to return Excalibur to where it was found as he dies. Merlin gives back the sword to the Lady of the Lake. Merlin accuses her of lying to him about the guardian of Camelot, but she explains that it was Galahad who was the true guardian and could have averted all this, though she assures Merlin that Arthur's death is not his fault. Merlin encounters Frik among the survivors of Arthur's army, who warns him that although Mab is significantly weakened, she is still dangerous. Merlin confronts Mab at Camelot, but the ensuing magical duel ends in a stalemate. Mab sneers that she is invulnerable to conventional means of destruction, but Merlin responds that she will be defeated when she is forgotten. Mab slowly fades into nothing as Merlin, Frik, and the entire court of Camelot turn their backs on her and walk away. Merlin is again shown back in the present, finishing his story. Frik reminds Merlin that he remembers things differently. Merlin admits that what Frik said is true, but he could not tell
that story to his listeners. Frik leads Merlin to Merlin's aged magic horse Rupert, who Frik says will take him to Nimue. Frik explains that sometime after Mab disappeared, the spells she had cast lost their effectiveness, and Nimue was set free. Merlin finds the elderly Nimue at Ambrosia's old forest home. He manages one last act of magic to restore them both to youth so they can finally live out their lives together. ==Cast==