Gawain tries to get revenge against Launcelot when he hears about the death of his brothers. He gets Arthur to lay siege to Joyous Gard, but the pope requires Arthur and Launcelot to make peace. Gawain is even angrier, and he then insists on Arthur's attack of Launcelot's lands. Launcelot refuses to fight Gawain because of their prior closeness. Gawain finally calls Launcelot a traitor and shames him in front of his people. Forced to defend his honor, Launcelot fights him and wins, refusing to kill him. After three weeks of healing, Gawain again challenges Launcelot, forcing him to fight. Though Gawain is almost dead, Launcelot again refuses to kill him, leaving Gawain lying on the field of battle, screaming his rage against Launcelot.

When Gawain dies, he tells Arthur it's his fault that Arthur's kingdom is being threatened. He admits his revenge against Launcelot was not right and he let pride overcome him. He writes to Launcelot before he dies, asking him to help Arthur and to pray at his tomb. Then he dies from the wound he suffered at the hands of Launcelot.