This chapter starts off with Malory telling us about a great new villain character he’s come up with, Lady Annowre.  She’s a sorceress who wants to marry King Arthur, and won’t take no for an answer!

“Pretty original, huh?” says Malory.

One time Arthur was at Cardiff, and Annowre came in and ensorcelled him.  He ran off with her to her lair in the north of Wales, but every time she started to get hot and heavy with him, he’d shake off his enchantment and remember that he was a married man.  Then Annowre would have to re-ensorcell him, and start the whole process over.  She was getting pretty frustrated, and starting to consider her backup plan, which was just to kill him.  Meanwhile a bunch of other knights, Launcelot and all, go to North Wales in search of their king.

But we’re not talking about Launcelot right now!  We’re talking about Nimue.  Nimue, stuck with the job of advancing the plot whenever Malory can’t think of a more elegant solution, rides out in search of Sir Tristram.  She finds him, of course, because she’s magic.

“Sir Tristram!” she cries.  “We’ve never met, but I’m glad to have bumped into you, because a terrible crime is going to be committed in about two hours, unless you stop it.”

“All right, mysterious pretty lady,” says Tristram.  “I guess I’ll stop it, then?”

“I’ll magic us over there, hold on.  Be aware we’re going to save the best guy ever.”

“Seriously?  Sounds like a pretty cool strange adventure.”

“I’m talking about King Arthur himself, Tristram.”

“Oh?  Well, yeah, I’ll help him, regardless of the strangeness or lack thereof.”

So Nimue and Tristram ride, semimagically, to Lady Annowre’s castle, where they crash her Murder King Arthur party, already in progress.  Arthur stands on foot, assailed from two sides by two knights, stuck wielding a tree branch or something because Lady Annowre is sitting back on a throne, holding Excalibur and laughing and watching.  One of the two knights knocks Arthur down, and Annowre jumps up with Excalibur, ready to slice Arthur’s head off.  But then!  Tristram bursts in and kills the two knights!  Nimue heals Arthur with magic!  Annowre tries to escape, but Arthur seizes Excalibur and decapitates her!  It’s pretty exciting!

Afterwards Nimue claims Annowre’s head, for magical a-doings-with, and Tristram introduces himself to Arthur as Sir Incognito, the Anonymous Knight, for no particular reason.  Tristram’s a jerk!

Anyway, once one of Arthur’s knights finds Annowre’s castle — specifically Sir Ector the Lesser, you remember him — Tristram excuses himself and leaves, because it’s gotten to be about time to pick Sir Kehydius up from the forester’s hut where Tristram left him back in Chapter XII.  Tristram’s just been wandering around North Wales, killing time since then.