Sir Aglovale returns to Camelot and swears revenge on the Orkney faction for having killed his brother Lamorak. Arthur convinces Aglovale that the only way to stop the bloodshed is for him to give up on revenge. Aglovale tells Arthur about the adventures of his youngest brother, Sir Percival, who is also a holy knight like Galahad. Percival has some adventures in a magical forest and then boards a magical barge with Sir Bors and Sir Galahad. In the barge, they are joined by Percival’s sister, a holy nun. On their search for the Holy Grail, the three knights get into a fight with a group of men and slaughter them. Galahad tells them the slaughter is not sinful, since the murdered men were not christened. They then come to another castle, where Percival’s sister sacrifices her life to save a woman with a fatal disease. After telling his stories, Aglovale asks Arthur to invite the Orkneys to dinner on his behalf.
Other returning knights bring contradicting rumors about the adventures of Bors, Percival, and Galahad. Rumors fly that Lancelot has died or gone mad. Guenever becomes less cautious, and Mordred and Agravaine wait eagerly for her to reveal her affair. Lancelot returns to Camelot exhausted but sane. Uncle Dap tells Arthur that Lancelot has been wearing a hair shirt—a painful way of doing penance for one’s sins.
The next day, Lancelot tells Arthur and Guenever the story of his search for the Holy Grail. Guenever, now forty-two years old, has dressed up and put on makeup in an effort to look good for Lancelot, and his heart warms at the sight of her. Lancelot tells them that he did not find the Holy Grail, which was reserved for Galahad. Lancelot also says that if Galahad seems cold, it is because he is more angelic than human. Lancelot relates that Galahad defeated him in jousting. Lancelot then confessed his sins, which he thought would make him the best knight in the world again. But he was then beaten by another group of knights, after which he fell asleep in a chapel. When he woke up, his sword and armor had been taken from him. He then began to wear the hair shirt as penance. Thinking he had cleansed himself and could fight as well as he had before, Lancelot fought a knight dressed in black but was again defeated.
Arthur is outraged that Lancelot, his best knight, has been beaten. Lancelot continues with his story: he then got on a magic barge, and Galahad soon joined him. Eventually Galahad got out to seek the Holy Grail. The barge eventually returned to the castle where the Grail was located, and Lancelot was allowed to watch Galahad and other holy knights participate in a Mass in a chapel that contains the Holy Grail.
Having found God, Lancelot decides to end his affair with Guenever, but she is confident he will return to her. The narrator explains that Guenever is not an evil seductress, for seductresses usually leave men hollow, while both the men that Guenever loves have accomplished great things.
Guenever’s faith in Lancelot’s love grows weaker as time passes. One day, she demands that he go on another quest instead of torturing her with his presence. Just as Lancelot has decided to give up his abstinence and rekindle his affair with Guenever, she leaves the room and refuses to talk to him. He leaves Camelot the next morning.