The Once and Future King Plot Summary
Young "Wart" is the adopted son of a minor nobleman when he meets Merlyn, a kindly magician, who takes him on many adventures, turning him into several different animals and teaching him skills, both mental and physical. Wart is very happy and learns to treat people with respect and kindness. Soon after ,Wart pulls a magical sword from a stone, which proves him to be the rightful king of England (his real father was the recently dead King.) Merlyn, who knew this from the start, advises Wart-now called Arthur-on how to be a good king. What Arthur really wants to do is end chaos that passes for law in his country. He wants his men-the knights of the round table-to help defenseless people and prevent the rich and strong from simply dominating everyone. Many young knights love the idea and admire Arthur. Lancelot, who becomes the best knight in the world, and Arthur's best friend, still wrestles with self-doubt. Soon after he comes to court, he falls in love with Arthur's wife, Guenever. Arthur knows they are having an affair subconsciously, but he wants to pretend it isn't happening, so the three are able to live in relative harmony for many years.
Arthur builds the Round Table into a predictable form of justice. Other prominent knights include the brothers of the Orkney clan, sons of the witch Morgause, Arthur's half-sister. Their names are Gawaine, Gaheris, Agravaine, Gareth and Mordred. These men are close-knit and hot-tempered. They love Arthur but come from a family that has always hated England, and the youngest, Mordred, is in a dangerous position. He is actually the son of Arthur and Morgause (she seduced her half-brother when he was young and vulnerable.) Since he is younger and has a different father from his brothers, Mordred feels out of place and hated by everyone around him, and he is angry and looking for revenge. Since Guenever has never had children, Mordred is Arthur's only offspring and therefore could become king if he can upset the court. He sees his chance with Guenever and Lancelot.
Mordred knows that because Arthur is just, he will not be able to avoid punishing an illegal act (adultery and treason), even if it involves his best friends. Though both Lancelot and Guenever love Arthur, they themselves are so in love that they cannot stay apart. Lancelot is tormented by guilt, always trying to do the right thing, believing that he must punish himself, but never finding the strength to end the affair. Finally, Mordred forces Arthur to recognize their affair, and once it is recognized, Arthur has no choice but to prosecute his wife and his best friend. The court begins to crumble as everyone is forced to take sides. Arthur's peaceful vision is undermined by Mordred's schemes. Lancelot kills Gareth, Gaheris and Agravaine, only because he has to, but Mordred convinces Gawaine it is because Lancelot has always hated their family. Gawaine swears he will never forgive Lancelot and makes sure Arthur will not either. Arthur leaves the castle, forced to fight Lancelot in France, and Mordred convinces the public he is dead, forcing Guenever to accept his marriage proposal.
At this point Arthur is very old, but he still remembers his original vision of brotherhood, for a time realized with the Round Table. Listening to the sounds of warfare outside, he brings in a young boy and tells him his story, so that it will not be forgotten. Arthur recognizes that he must die and is at peace with this, knowing that his ideas for law and justice will return. The story pulls backward, explaining that each person's fate is one drop in the ocean of life. Lancelot and Guenever become a priest and nun, and Mordred is killed. But the vision lives on: Arthur is the "once and future king."