King Mark, jealous as ever, and disgusted by the incessant talk of Tristram's virtues, decides to capture and murder Tristram. His men refuse the plot, and when he murders one, the rest say they will go to Arthur and declare him a traitor. Mark says he will go himself and rides away. He meets Sir Lamerok and Sir Dynadin, fights them and loses miserably, then rides with them, not revealing his name. At Tor's castle Mark is found out, and Dynadin, much as Mark disgusts him, decides to conduct him on the way to Arthur. They meet a group of Round Table knights and Mark flees.
Led by Arthur's fool, the Round Table knights trick and mock King Mark and chase him through the forest hooting and howling until Mark has the luck to stumble onto Sir Palornydes, who protects him. Mark rides with his protector until Palomydes abandons him in disgust. Alone again, Palomydes stands in the forest bemoaning his hopeless love of Isode, and both Mark and Dynadin overhear him. Mark sneaks away and, for lack of anywhere else to go, goes to Camelot to suffer Arthur's judgment. He jousts with Amante and by a cowardly stroke kills him, then flees. Launcelot brings him back, for love of Tristram, and Mark swears on the Bible that he will now be Tristram's faithful lord — a lie, of course. Meanwhile Palomydes fights Lamerok, neither knowing who the other is, then the two ride separately to the tournament Arthur has announced at Camelot.
At the tournament, Gawain wins the first day's prize. On the second, he and his brothers are overthrown by Lamerok and swear vengeance. The enmity between Gawain's brothers and Lamerok is an old one. "And wyte you well, my fayre bretherne," Gawain says, "that this sir Lameroke woll nevyr love us, because we slew his fadir, kynge Pellynor, for we demed that he slew oure fadir, kynge Lotte of Orkenay; and for the deth of kynge Pellynor sir Lameroke ded us a shame to oure modir. Therefore I woll be revenged."
Soon after the tournament, Lamerok goes to the lady he has loved and served, Lot's widow, Gawain's mother. Gaheris comes into the bedroom, kills his mother, and says he will kill Lamerok if they meet when Lamerok is armed. Gawain's brothers Mordred and Aggravain fight Dynadin because of his friendship with Lamerok.
Meanwhile King Mark, safe in Cornwall, writes a scornful letter to Arthur and another to Guinevere accusing her of faithlessness. Mark's enemies invade his land and, little as he likes it, he is forced to ask Tristram's help. Tristram deploys Mark's forces, fights nobly himself, and wins Cornwall's battle. Afterward a song mocking King Mark is sung at Mark's court — a song composed by Dynadin. Mark is sure Tristram had a hand in this, but he can do nothing.