Plot
Morgaine, priestess of Avalon, is King Arthur's half-sister. Their mother, Igraine, married king Uther Pendragon after Morgaine's father, Gorlois, died in battle. Rumors spread in Avalon that, before Igraine knew of Gorlois's death, Uther consulted with Merlin, who used magic to give Uther Gorlois's appearance and, thus, gain access to Igraine at Tintagel. He had sex with her and they conceived Arthur. Morgaine witnesses Uther's accession to Caerleon's throne after his predecessor, Ambrosius, dies of old age. Uther becomes her step-father, and he and Igraine have Arthur.
When Morgaine is eleven years old and Arthur six, there is an attempt to murder Arthur. Their maternal aunt, the high priestess Viviane, arrives in Caerleon and advises Uther to have Arthur fostered far away from the court for his own safety. Uther agrees, and allows Viviane to take Morgaine to Avalon, where she is trained as a priestess of the Mother Goddess. During this period, Morgaine becomes aware of the rising tension between the old Pagan and the new Christian religions. After seven years of training, Morgaine is initiated as a priestess of the Mother, and Viviane begins grooming her as the next Lady of Avalon.
Months after her initiation, Morgaine is given in a fertility rite to the future high king of Britain. Their union is not meant to be personal, but rather a symbolic wedding between him and the land he is to defend. They have sex, and the following morning, they talk and each reveal themselves as Morgaine and Arthur. After recognizing each other, they are horrified to realize what they have done. Two months later, Morgaine is devastated to find that she is pregnant.
After Uther dies fighting the Saxon invaders, Arthur claims the throne of Britain despite questions about his legitimacy (he was conceived within days of Igraine's marriage to Uther). Since Arthur must now defend Britain against the Saxons, Viviane has Morgaine make him an enchanted scabbard that will prevent him from losing blood and gives him the sacred sword Excalibur. With the combined force of Avalon and Caerleon, Arthur repels the invaders and marries Gwenhwyfar.
As Morgaine's unborn child grows within her, so do her feelings of anger and betrayal toward Viviane, who she believes tricked her into bearing a child to Arthur. Unable to stay in Avalon any longer, she leaves for the court of her aunt Morgause, queen of Lothian, where she gives birth to her son, naming him Gwydion. Spurred by her husband Lot's ambition and her own, Morgause tricks Morgaine into allowing her to rear her son. To escape Lot's unwanted advances, Morgaine leaves Lothian and returns to Arthur's court as a lady-in-waiting to his queen, Gwenhwyfar. She does not see Gwydion again until he is grown and a Druid priest.
When Gwenhwyfar fails to produce an heir, she is convinced that God is punishing her for her sins. She considers her greatest sins to be her failure to persuade Arthur to outlaw pagan religious practice in Britain and her forbidden love for Galahad, Arthur's cousin and finest knight, also known as Lancelet. Although Lancelet reciprocates Gwenhwyfar's love, he is also Arthur's friend and an honorable man. This situation causes suffering to both Lancelet and Gwenhwyfar. Meanwhile, Morgaine also falls in love with Lancelet.
On the eve of a decisive battle against the Saxons, Gwenhwyfar prevails upon Arthur to put aside Uther's Pendragon banner and replace it with her own Christian banner. As her religious fanaticism grows, relations between Avalon and Caerleon grow strained. Still, in her desperation over her failure to carry a child to term, she asks Morgaine for help, threatening to have an extramarital affair so she can become pregnant. In an attempt to keep Gwenhwyfar from doing so, Morgaine reveals to Gwenhwyfar that Arthur already has a son, though he does not know it. Later, Arthur asks Lancelet to join him and his wife in his bed to conceive a child, stating that the child would be conceived on his bed, and to satisfy the suffering of both Gwenhwyfar and Lancelet. Lancelet at first refuses, but is finally convinced; however, no child is conceived even from this.
After the battle, Arthur moves his court to Camelot, which is more easily defended than Caerleon was. Seeking to free both Lancelet and Gwenhwyfar from the forbidden love that traps them both, Morgaine tricks Lancelet into marrying Gwenhwyfar's cousin, Elaine. Later, during a dispute with Arthur over their lack of an heir, Gwenhwyfar breaks Morgaine's confidence and tells Arthur of Gwydion. Arthur summons Morgaine and orders her to tell the truth, and she obeys. Now believing that the lack of a royal heir is God's punishment for Arthur's union, however unwitting, with Morgaine, Gwenhwyfar urges Arthur to confess the encounter to the bishop, who imposes strict penance upon him. Then she and Arthur arrange for Morgaine to marry into Wales, far from Camelot. But because of a misunderstanding, Morgaine, who thought she would be marrying the king's younger son Accolon, a Druid priest and warrior, finds herself betrothed to King Uriens of North Wales, who is old enough to be her grandfather. Arthur yearns to meet Gwydion and perhaps foster him at Camelot, but each time he brings up the subject with Gwenhwyfar, she refuses to discuss it. Meanwhile, Gwydion is taken by Viviane to Avalon.
Morgaine marries Uriens and moves to North Wales as its queen, and enjoys a good friendship with him, and his youngest son, Uwaine, whom she starts considering as her own son. Years later, she begins an affair with Accolon. The "old people" of the hills, who keep to the old pagan ways, regard Accolon and Morgaine as their king and queen. Uriens suspects nothing, but Accolon's older brother, Avalloch, begins to; he eventually tries to blackmail Morgaine into sleeping with him as well. Morgaine sends Avalloch out on a boar hunt and magically has him killed by the boar. In his grief for his eldest son and heir, Uriens abstains from pork for the rest of his life.
Gwydion, now grown, goes to the Saxon courts to learn warfare far from Arthur's eye. Impressed by his cleverness, the Saxons name him Mordred ("Evil Counsel"). Years later, at a Pentecost feast at Camelot, he introduces himself as Queen Morgaine's son and Queen Morgause's foster son, though he calls Queen Morgause "Mother" and Morgaine by her name. Because of his resemblance to Lancelet, he must often tell people that Lancelet is not his father. To earn his knighthood with no suspicion of preferential treatment, Gwydion challenges Lancelet to single combat during a tourney and they fight. Gwenhwyfar, who warmed to Gwydion in the meantime, protests and Arthur interrupts the match. Lancelet makes Gwydion a knight of the Round Table, naming him Mordred.
Morgaine tells Accolon, who is now Uriens's heir, of the sacred marriage she made with Arthur years before. She adds that they must take the kingdom back from Arthur and the Christians and bring it back under the sway of Avalon. Meanwhile, Morgaine gets pregnant and is not sure if the child is Uriens' or Accolon's, but has an abortion because she is too old to give birth safely. The attempted coup fails and Arthur kills Accolon in single combat, sending a warning to Morgaine. As Uriens recovers from the shock of losing a second son and his wife's betrayal, Morgaine leaves Wales forever and returns to Avalon.
Morgaine returns to Camelot years later, disguised, with another sister of Avalon, during the Pentecost festival. At the start of the holy rites, the Sacred Regalia of Avalon, the sword, the spear, the dish, and the cup, are presented to the church as an offering, having been stolen from Avalon. Enraged and wielding great magic, Morgaine invokes the Great Mother Goddess to retrieve them. The assembled court sees the manifestation of the Grail as a holy revelation and Morgaine as the Virgin Mary. When the knights of the Round Table leave to search for the Holy Grail, Mordred attempts to usurp the throne. The armies of Arthur and Mordred eventually fight but in the end, Mordred dies and Arthur is mortally wounded. Morgaine takes the dying Arthur through the mists to Avalon, reassuring him that he did not fail in his attempt to save Britain from the approaching dark times. Arthur dies as the shoreline comes into view. Morgaine buries him in Avalon and remains there to tell the tale of Camelot.
