Howel, King of Brittany, turns out to have a problem.  This one earl, Grip, has been making trouble for him: refusing taxes, assaulting officers, laying siege to Howel’s house, that kind of thing.  As you may recall from Book V, Brittany has a severe heroic knight shortage, such that when Howel’s wife was abducted and eventually murdered by a rampaging giant, all Howel could do was sit back and hope for the best.  That was years ago, and now Howel’s son, Sir Kehydius, has grown up.  Kehydius tries to joust with Earl Grip, but it doesn’t go very well for him.

“I don’t know what I’m going to do, here,” Howel says afterwards.  “My son’s not up to the task of defeating Grip, and of course I and all my retainers are much too old.”

“Listen, sire, I have a suggestion.”  It’s Gouvernail.  “My lord Sir Tristram is incredibly valiant, up there in the highest echelons of knightliness alongside Sir Launcelot and his kind.  Ask him to fight this Grip for you.”

“Makes sense,” says Howel.  “All of Brittany is agog with tales of Tristram’s valiance.  I don’t know why I didn’t think of it myself, actually.”

So Howel talks to Tristram, and Tristram agrees to joust Grip, and he does, and he wins, and then there’s a party.

Afterwards Howel announces his retirement — he’s too old to defend Brittany against giants and troublemakers like Grip.  And since his own son Kehydius is laughably inadequate, he offers his kingdom to Tristram.

“Sounds good,” says Tristram.

“One condition: you need to marry my daughter, Isoud the White.”

“Hmm,” says Tristram.  “Your whole kingdom, you say?  Well, there is this small matter of… on the other hand, she’s married to my uncle… on the other other hand, I’m supposed to be bound by the oaths of courtly love…. on the other other other hand, the whole kingdom… mmm…. okay.  Okay!  I’ll marry your daughter.” says Tristram.

CUT TO the wedding night of Tristram and Isoud the White.

“Just a quick sidebar, I’m not going to sleep with you,” Tristram tells her.

“What?”

“I can’t sleep with you, Isoud.  I’m in love with Isoud.  I’d have mentioned it sooner but then I wouldn’t have gotten your father’s kingdom.”

“Wait, what?” asks Isoud the White Hand.

Tristram explains: he’s a jerk!  There are other components to the explanation but I don’t think we can understate the jerk thing.  Isoud the White Hand isn’t exactly thrilled with the news, but she accepts the situation.  So Tristram and Isoud don’t have sex!  Malory is very clear on this.  Second base only, he says.  You think I’m kidding?  “Other cheer made he none but with clipping and kissing.”  Boom!  Direct quote.

Then this troublemaker Sir Suppinabiles, one of Sir Kehydius’s friends, visits Camelot and tells everyone all about the new King of Brittany, Tristram of Liones.  When Launcelot hears about it he does a spit-take.  “What?  He married Isoud?  But he’s in love with Isoud!  You don’t get to marry some random wench when you’re in love with a king’s wife!  That’s ridiculous!  How dare he?  How dare he?”

“Launcelot, my friend.  You seem to be taking this news awfully personally,” says King Arthur.  “Is there something I should know?”

“No,” say Launcelot and Guenever in unison.

“Well, that’s good.”

“It just burns my biscuits, is all,” Launcelot continues.  “I always liked Tristram, even though we met only briefly offscreen during the events of Chapter XIX.  But if he’s going to go around marrying the wrong Isoud like that, he and I aren’t friends.  You tell him I said that!  Next time I see him, we joust!  We joust for realsies!”