Chapter 1 One day in May, Agravaine says openly, among many knights, that it is shameful for Launcelot to sleep with the queen, and for them to all know it and do nothing. Gawaine, Gareth, and Gaheris say they will not continue such talk, but Mordred agrees with Agravaine, who says he wants to tell the king. Gawaine tries to remind Agravaine of how often Launcelot has saved both Arthur and Guenever, as well as many knights’ lives. Arthur then comes into the chamber. Gawaine asks them to be quiet, and leaves with Gareth and Gaheris.
For the first time, the affair between Guenever and Launcelot that has long been common knowledge at court breaks out into the open, as Agravaine, seemingly out of jealousy, proclaims what everyone knows to be true, but has kept quiet out of respect for Guenever, Arthur, and Launcelot, and for fear that the court and even, perhaps, the very kingdom may begin to unravel.
Chapter 2 Agravaine announces to Arthur that everyone knows of Launcelot’s affair with Guenever. Arthur is reluctant to believe it, since Launcelot has done so much for him and Guenever, and since he loves him. Agravaine tells Arthur to go out hunting, alerting Guenever that he’ll be gone that night: he and Mordred will take Launcelot captive with the queen. The king agrees. Agravaine and Mordred gather 12 knights. That night Launcelot tells Sir Bors he’ll go to the queen, but Bors counsels him not to, saying he’s suspicious of Agravaine. Launcelot isn’t worried, and tells Bors he won’t be a coward.
Agravaine chooses not to listen to his brothers Gawaine, Gareth, and Gaheris, who have split off from Agravaine and Mordred concerning whether or not to share the truth with Guenever. While Arthur’s full inner emotions are not shared with us, it seems that he reacts ambivalently, both refusing to believe the news immediately, and curious enough to know whether or not it’s true that he agrees to Agravaine’s plan.
Chapter 3 Launcelot goes to the queen’s chamber, and Agravaine, Mordred, and their knights surround them, calling to Launcelot to yield. Launcelot has no armor and cries that this is shameful. Launcelot kisses Guenever and tells her, if he is killed, to escape with Sir Bors and Urre, who will take care of her.
Launcelot’s decision to sleep with Guenever anyway is shown to be overly prideful, as he even puts her into danger once the knights surround them. The knights are now clearly divided into two camps.
Chapter 4 Launcelot opens the door such that only one knight can enter. Launcelot dodges his sword and hits him over the head with his bare hands, killing him. Launcelot arms himself with this knight’s armor. He then asks Agravaine to stop making such a scene, and says he will appear before the king the next morning to be properly charged with treason. Agravaine and Mordred cry that they’ll kill him now, so Launcelot opens the door and immediately kills Agravaine, wounds Mordred, who flees, and strikes down all the others. Launcelot returns to Guenever and tells her that Arthur must now be his enemy, but he will still try to rescue her.
Launcelot may not be able to fight one against a dozen knights, but he begins by killing the first knight in order to show that he is not a coward and is, as he long has been, a remarkable knight. But his slaying of the first knight is also just a warning not to continue, since he promises not to flee and instead to face proper accusation as a traitor. Agravaine and Mordred’s to accept this raises the stakes of the conflict, as does Launcelot’s killing of Agravaine.
Chapter 5 Launcelot escapes to Sir Bors, and tells him everything, saying that civil war has now come to the realm. Bors tells him that many knights will be on his side, and he calls Launcelot’s allies together. They promise to defend Launcelot.
Sir Bors has been predicting that Launcelot’s behavior, as well as that of his rivals, may well lead to disaster, but now he acts himself in accordance with his loyalty to Launcelot.
Chapter 6 Sir Bors counsels Launcelot to attempt to protect Guenever above all: regardless of the morality of their former actions, now it is his responsibility to defend her, especially if Arthur decides to burn her at the stake. Bors and the others say they will care for her if Launcelot is killed.
The book portrays Launcelot and Guenever’s affair ambivalently, and Bors’s position in particular is a realist one—rather than bemoaning lost chances, he counsels Launcelot to face current facts.
Chapter 7 Mordred, having escaped from Launcelot, rides wounded to Arthur and tells him what happened. Arthur cries that he is greatly grieved that Launcelot is against him, and that now the Round Table is broken forever. Guenever must be sentenced to death, which is the only punishment for treason. Gawaine asks Arthur to grant mercy to his queen, given that there could be another explanation for Launcelot’s presence in her chamber, and because of the great good that Launcelot has done. But Arthur refuses, saying that Gawaine has no reason to love Launcelot, who has just killed Gawaine’s brother Agravaine. But Gawaine says that he warned his brother, though he is sorry of his death.
Arthur seems almost as upset that Launcelot has fought against his fellow knights, contributing to the destruction of the Round Table, as he is that Launcelot has been having an affair with his wife behind his back. Indeed, the tragedy of these scenes is that none of the characters seem truly angry at each other, but they are forced to take drastic action because of the codes of honor and conduct they adhere to. Gawaine remains loyal to Launcelot as well as to Arthur, given that he cannot find a way to justify the dishonorable actions of his own brother. Despite Gawaine’s suggestions, Arthur believes that his knights’ actions will trigger a series of inevitable consequences.
Chapter 8 Arthur tells Gawaine, Gaheris, and Gareth to prepare Guenever for the fire. Gawaine refuses to assist in such a shameful death. Gareth and Gaheris say they will be present, but refuse to participate. Weeping, Gawaine returns to his chamber, while the queen is brought to the stake. Launcelot’s squire, who has been spying on the queen, alerts him that her death is being prepared. Launcelot charges in on horseback and kills many knights—including, by accident, Gaheris and Gareth, who are unarmed and simply by-standers. Launcelot rides to Guenever, takes her onto his horse, and they ride to Joyous Gard.
Gareth and Gaheris now position themselves firmly on the side of the queen and, by proxy, Launcelot. For a third time, Launcelot enters to rescue Guenever, but this rescue attempt does not go nearly as successfully as previous ones, and he accidentally kills knights who are both loyal to him and dear to Arthur. Chance and accident are crucial aspects of the book’s tragic finale.
Chapter 9 Arthur swoons from sorrow at hearing of the death of Gaheris and Gareth, crying that his fellowship is broken. He asks the other knights not to tell Gawaine of his brothers’ deaths for now, but someone sneaks off to tell Gawaine. Gawaine refuses to believe that Launcelot killed his brothers.
Arthur realizes that the fellowship of the Round Table is irreparably lost, but he still seeks to avert the worst of the damage, since he understands that the atmosphere at court could in fact grow worse.
Chapter 10 When Gawaine rushes to Arthur, Arthur tells him that Launcelot killed his brothers accidentally. Gawaine swears never to rest until he or Launcelot kills the other, and he asks Arthur to make war against Launcelot. The king summons knights from throughout England, and they prepare to lay siege: meanwhile, other knights join Launcelot, some for his sake and some for the Guenever’s sake. For 15 weeks Arthur’s men surround Launcelot’s castle.
Once Arthur is faced to face with Gawaine, he cannot lie to him. Now, although Gawaine had remained loyal to Launcelot and Guenever before (even when Launcelot killed Agravaine), his loyalty to his own family—especially since his brothers were blameless, unlike Agravaine—now triumphs, and his hotheaded temper takes over.
Chapter 11 Then one day Launcelot calls to Arthur and Gawaine to ask them to give up the siege rather than risk dishonor on the battlefield. Launcelot says he is reluctant to fight against such noble knights, but he will defend the honor of Guenever to his death—he reminds Arthur of all the times he saved her for Arthur’s sake. Launcelot says he regrets killing Gareth and Gaheris. Gawaine cries that he is a liar, and will war against him for his whole life.
Launcelot is reluctant to fight against Arthur’s knights, since it was never Launcelot’s own wish to create a rift between members of the Round Table. Arthur himself seems equally unwilling to go to war against his friend, but for some reason the king now appears to be driven by the will of Gawaine, who is still seeking to avenge his brothers’ death.
Chapter 12 Arthur would have just taken his queen and returned home, but Gawaine refuses to make any kind of compromise. They prepare to do battle, and in the morning all the knights meet: Launcelot asks his followers to spare Gawaine and Arthur if they can.
For Arthur, the most important thing has always been to maintain unity among his subjects, while for Gawaine, desire for revenge gains the upper hand. It seems strange that Arthur follows Gawaine’s wishes rather than his own, and this only adds to the tragedy of this conflict.
Chapter 13 Gawaine meets Lionel and strikes him down: the battle begun, many more are slain. Sir Bors strikes down Arthur and prepares to kill him, but Launcelot orders him not to, and he rehorses Arthur and asks him to stop the battle. Arthur, tears in his eyes, rides away from Launcelot, bemoaning the war. The next day Bors tries to avenge Lionel’s death by killing Gawaine, but they wound each other. Launcelot’s knights urge Launcelot to personally fight Arthur to end this battle. The Pope, meanwhile, sends a messenger, asking the sides to make peace.
Now, for the first time, knights of the Round Table do battle against each other not in the context of a friendly tournament, but to the death. Launcelot is walking a careful, fraught line by doing battle even while attempting to save Gawaine and Arthur. Even the Pope now becomes involved, suggesting just how high the stakes of the civil war in Arthur’s court have grown.
Chapter 14 Arthur wants to agree but Gawaine won’t make peace with Launcelot. Launcelot agrees to bring Guenever to Arthur in eight days, and they ride together to Carlisle.
Again it is Gawaine rather than the king of England himself who prevents peace, as his desire for revenge is so great that it starts to tear the kingdom apart.
Chapter 15 Launcelot cries that he’s brought Guenever according to the Pope’s command. He tells Arthur of Agravaine’s and Mordred’s treacherous actions, but Gawaine says they were right. Launcelot says he has always been loyal to Arthur and Gawaine, and reminds them that he’s rescued them many times.
Once again, Launcelot attempts to describe some of the mitigating actions that should allow Gawaine and Arthur to forgive him—both his own honor in defending them, and other knights’ dishonor.
Chapter 16 Gawaine says that the king can do as he wishes, but he himself will never forgive Launcelot. Launcelot says he is just as sorry to have killed Gawaine’s brothers, and he offers to go from church to church in penance for their sake. All the knights and ladies weep, but Gawaine refuses to accept this offer, and accuses Launcelot of treason. He vows to kill Launcelot wherever he can find him out of court.
Gawaine had turned from pledging loyalty to Launcelot to pledging loyalty to Arthur as Launcelot’s enemy, but now those very sides are disintegrating themselves, as Gawaine extracts himself from any kind of competitive alliance in order to vow individual vengeance.
Chapter 17 Launcelot, weeping, cries that he regrets ever coming into this kingdom, since he’s now leaving it in such a way. Launcelot says to Guenever that he will still vow to defend her from any wrongs. He kisses her and dares anyone to say that she isn’t true to Arthur. All weep as he leaves, except for Gawaine. Launcelot goes to his castle and draws his knights together, saying that he must leave this realm: they all vow to stay with him wherever he goes.
Launcelot’s departure from court is portrayed as a great tragedy, despite the fact that his affair with Guenever was always, legally speaking, treason. However, the book seems to privilege Launcelot’s honorable behavior as a knight more than it condemns his weakness with women, something for which he never repents (except during his quest for the Sangreal).
Chapter 28 A hundred knights leave with Launcelot for Benwick (Bayonne), and they become lords of these French lands. Launcelot crowns his knights kings and dukes of various lands.
Now Arthur’s court is officially split, as Launcelot’s men begin to spread out into foreign lands and create their own kingdom.
Chapter 29 Meanwhile Arthur and Gawaine prepare a great army to fight against Launcelot’s people. They sail to Benwick and lay waste to the lands. All Launcelot’s knights variously suggest how to respond, but Launcelot sends a messenger to Arthur to try to make peace. All except Gawaine are in favor of this.
Arthur and Gawaine have become the aggressors as they continue to seek to destroy Launcelot, even now that he has a foreign kingdom. But it is clear that Gawaine rather than Arthur is leading this attack.
Chapter 20 Gawaine tells the messenger that he hasn’t forgotten his promise to kill or be killed by Launcelot. Launcelot, hearing the answer, weeps. In the morning, Arthur’s knights besiege the city of Benwick. A battle begins, and the siege lasts for half a year, with much slaughter. Finally Gawaine calls to Launcelot not to hide inside his castle like a coward. The knights tell Launcelot he now must fight or be shamed. Launcelot calls down that he is reluctant to fight Arthur, but now must defend himself.
Now Launcelot realizes that he has lost his best attempt to make peace, and he must be forced to do battle against Arthur’s men. A siege, rather than a face-to-face battlefield fight, suggests just how passively Launcelot wants to respond to Gawaine’s aggression, so as to prevent bloodshed. But finally, to protect his honor he must meet Gawaine.
Chapter 21 Gawaine and Launcelot come together, and their horses fall to the earth. They continue on foot, both wounding each other. Gawaine’s strength increases from the morning until noon thanks to a holy man’s gift. Launcelot marvels at his strength. But past noon Gawaine’s strength ebbs, and Launcelot doubles his strokes, striking him down. Launcelot turns to withdraw: Gawaine orders him to kill him, but Launcelot says he’ll never kill a fallen knight.
Gawaine and Launcelot are only equally matched initially because Gawaine has been strengthened through this magical gift. However, when they fight with only their natural skills, Launcelot once again shows himself to be the greatest. He refuses even to end the civil war by killing Gawaine dishonorably.
Chapter 22 The king regrets that this war was ever begun. Gawaine lies wounded for 3 weeks. Finally he returns to the castle gates and orders Launcelot to come down. Launcelot and Gawaine fight again for three hours: then again Gawaine’s strength ebbs, and Launcelot strikes Gawaine in the old wound. Launcelot again refuses to kill him. Gawaine lies wounded for a month and then prepares to fight again.
With Gawaine wounded but not dead, the civil war is doomed only to be paused rather than ended. This scene is one of notable repetition with the earlier battle scene, suggesting that the two sides seem condemned to constant, unending battle between each other—despite the fact that neither considers the other a true enemy.