But now Tristram's identity is discovered. Reluctantly, King Angwyssh expels him from court; Tristram says farewell to Isode and returns to Mark at Tentagil Castle. He serves Mark for some time, but at last Tristram and Mark fall out over a lady, the wife of Sir Segwarydes. Mark tries to murder Tristram, but fails. Soon afterward Tristram finds the lady not worth his love, as he thinks, and vows he will henceforth "beware what maner of lady I shall love or truste."
Mark, still plotting to murder Tristram, sends him after Isode, whom he intends to marry on the basis of Tristram's praise of her. Tristram's ship is driven to England in a storm, and there by chance King Angwyssh has been summoned to defend himself against an accusation of murder. Tristram offers himself as Angwyssh's champion in a trial by combat and fights Launcelot's cousin Blamoure. He beats him but refuses to kill him, and so Tristram both frees King Angwyssh and becomes a friend of Launcelot's house. King Angwyssh offers Tristram any gift he may ask, and Tristram requests Isode, not for himself but for Mark, as his mission requires.
Isode and Tristram sail for Mark's court in Cornwall. On the way, a love potion prepared for Isode and King Mark accidentally falls into the hands of Tristram and Isode, who unwittingly drink it and thus seal their unlucky love. Before reaching Cornwall Tristram has further adventures which by chance parallel adventures Launcelot is undergoing at the same time. Then the lovers arrive at court; Isode and Mark are married, but she and Tristram remain lovers.
