Director Gregory Doran and adaptor Mike Poulton summarise the plot of this complex set of stories:
Having become High King of Britain after pulling the sword from the stone, Arthur is faced with a rebellion led by King Lot and King Uriens who questions his legitimacy.Lot sends his wife Margawse to spy upon Arthur's court but Arthur seduces her and gets her pregnant.
With Merlin's help, Arthur recruits the champion knight Pellinore and gains the sword Excalibur. During a vast battle Arthur defeats Lot's forces, and Lot is killed by Pellinore. Arthur makes peace with Lot's sons Gawain and Agravain. He marries Guenever and is presented with the Round Table by her father, around which Arthur makes all his knights swear a chivalric oath.
Margawse gives birth to his bastard son Mordred.
Morgan Le Fay plots with her lover Accolon to steal Excalibur and kill Arthur and her husband.
Meanwhile, Merlin has become obsessed with the nymph Nimue and attempts to take her maidenhood, but is himself enchanted and trapped for all eternity under a giant rock.
Arthur fights Accolon and, with Nimue's help, defeats him and recovers Excalibur.
A young man arrives at court, mysteriously dressed as a bear, and is placed under supervision in the kitchen, mockingly named Beaumains.
Meanwhile Gawain and Agravain ambush and murder Pellinore.
A year passes and a damosel, Lynet, comes to Arthur's court to seek aid for her sister who is imprisoned by an evil knight. Beaumains pleads for this adventure, and Arthur grants it to him, and makes him a knight. After confronting and defeating the Red Knight, Beaumains reveals himself at court to be Gareth of Orkney, youngest son of Lot and Margawse, and asks Arthur to marry him to the now-smitten Lynet.
An adventuring Gawain agrees to help King Pelleas gain the love of the Lady Ettard but instead he betrays him and seduces Ettard himself. On discovering this betrayal, Pelleas vows to starve himself to death. Nimue nurses him back to health and Ettard, upon waking, pleads Pelleas' forgiveness because she has fallen in love with him. Pelleas rejects her and leaves with Nimue.
At Pentecost, the Holy Grail appears before all the knights covered in white samite (a heavy silk fabric). After it leaves, all the knights swear to search for it until they can see it uncovered. Their quests take them to the end of the world, where Gawain and Launcelot fail in their quests, but Percival, brother to Lamorak, eventually achieves it.
A tournament is held. Launcelot decides to enter it in disguise, wearing the token of Elaine of Astolat. Launcelot wins great glory at the tournament but is wounded. Elaine, finding Launcelot, swears her love to him. She is rejected and dies with grief.
Launcelot and Guenever resume their affair. To prove their liaison to Arthur, Mordred and Agravain trap Launcelot and Guenever in her chamber, where Launcelot kills Agravian and twelve other knights. Arthur demands Guenever be burned at the stake. Launcelot organises a rescue party, but in the throng accidentally kills the unarmed Gareth. Gawain is heartbroken at the death of his brother and demands Arthur declare war on Launcelot. They besiege Launcelot's castle until the Cardinal Bishop of Rochester intervenes and demands that Launcelot return Guenever and accord with Arthur. Gawain rejects the idea and forces Arthur to pursue Launcelot to his lands in Beaunne, France, leaving Mordred as regent of England.
In Beaunne, Launcelot fights Gawain, felling him with a mighty blow but not slaying him.
Meanwhile Mordred has declared Arthur dead, himself king, and that he shall wed Guenever. When Arthur hears this, he returns to England; fighting and defeating Mordred's forces at Dover. Arthur wins the combat and slays Mordred, but is himself mortally wounded and is carried into the Vale of Avilion.
Launcelot arrives too late to save Arthur but seeks to rescue Guenever. She rejects him and dedicates herself to God. Launcelot joins a monastery where he dies, and his soul ascends to heaven.
Photo by Ellie Kurttz shows David Rubin (left) and James Traherne (right) as knights in the RSC's 2010 production of Morte d'Arthur © RSC