Knowing that the tournament at Surluse has been set up as a way of killing Launcelot, Mark sends Tristram in hopes that he will be mistaken for the disguised Launcelot. Tristram is hurt but not killed, and Mark, offering to dress his wounds himself, gets Tristram alone and throws him in a dungeon. Percival of Wales rescues him; Launcelot gives Tristram and Isode his own castle, Joyous Gard; and Mark is thrown in prison by his own vassals. While at Joyous Gard, Tristram goes hunting every day, taking arms with him at Isode's request. He meets Palornydes, Ector, Bereuse Saunz Pit, and others.
Word comes that Lamerok has been murdered by Gawain and Gaheris, and when Tristram meets them he spares them only for love of Arthur. He later meets Gareth, Gawain's nobler brother, and finds him repelled by the treachery of his brothers. Later Tristram and his companions come upon a barge carrying the murdered king of the Red City, in whose dead hand lies a letter asking for vengeance. Palornydes takes the quest and departs. Tristram and the rest have adventures of their own. Throughout this tale Sir Dynadin scoffs at lovers and repeatedly gets buffeted by mistake because of other people's love affairs and jealousies.