Tristram heads back to Cornwall, where he meets up with his father King Meliodas and his uncle King Mark and his stepmother Queen o’ Brittany, and they’re all thrilled by his having returned from Ireland whole and hale and hearty. There’s a tremendously big party and Meliodas and Brittany give Tristram the bulk of his inheritance, just because.
Afterwards, Tristram hangs out in Mark’s court. He’s on the market for a lady-love, the lovely Isoud already forgotten apparently, and he sets his cap on a certain woman whose name Malory couldn’t bothered to learn. Her husband — yes, this woman is a married woman, which is probably what stops Malory from calling her a damosel — anyway, this woman’s husband is named Earl Segwarides. I’m suspicious; it looks like Malory just mashed his fingers on the keyboard and deleted consonants until he had an acceptable number of syllables. Might as well call him Earl Furewunumuh, which is a name I made up just now by that method. Anyway, I’ll call her Sally.
Tristram and Sally are chilling at Mark’s court, having an affair, like you do, and everyone’s cool with it. Tristram’s cool with it, Sally’s cool with it, Segwarides is entirely down with it on account of he doesn’t know about it, and Mark… okay, Mark’s not cool with it. Not because of anyone’s marriage vows or promise ring! No, Mark’s upset because he wants to have an affair with Sally. Sally, for her part, is into having a husband and two lovers, and doesn’t see why Mark and Tristram aren’t cool with that.
But she can’t have her cake and eat it too, so to speak, so Sally comes up with a plan to determine which of her two lovers she should pursue her affair with, Mark or Tristram. Naturally, Peter the dwarf is involved.
“Ho, Tristram!” says Peter. “I bear a message from Sally to you.”
“Lay it on me,” says Tristram.
“She says that she can’t sleep with you until tomorrow night. Tonight she’s sleeping with someone else.”
“What? No! Unacceptable!” fumes Tristram.
“I’m not done. Whatever you do, she says, don’t show up in her bedchamber expecting to sleep with her tonight, and especially don’t come unarmed, because her other lover will be well-armed and if you show up, there’ll be nothing for it but for you and he to joust for her love, right there in her bedchamber, which she thinks is going to be extremely hot.”
“Oh, I’ll show up,” says Tristram. “I’ll show up and I’ll bring a sword and I’ll kill him! No one else gets to sleep with Sally — not her other lover, not her rightful husband, nobody!”
“Yeah, okay, I’ll tell her to expect you around, what, ten o’clock?”
So Peter heads back to Sally to pass on the message. But before he gets to her, he bumps into Mark. Malory doesn’t specify, but I assume Mark recognizes him.
“Peter! Why, as I live and breathe, Peter the dwarf! I haven’t seen you in, my, it’s been six books, my good man. How’s Mister Two-Swords? And that one fellow whose name I never learned?”
“They’re both dead,” says Peter.
Mark pauses for a respectful moment of silence.
“You know, he named-dropped Tristram,” he says, once the moment has passed. “The fellow whose name I never learned. Didn’t mean anything at the time.”
“Mmm,” says Peter.
“Speaking of my nephew, I couldn’t help but notice you were closeted in conversation with him, Peter my good man. What, I pray thee tell me, was the subject of your little conspiracy?”
“Can’t tell. Secret.”
“Tell me or I stab you,” Mark says with uncharacteristic force.
“Jeez, fine,” says Peter. “Everyone’s always with the threaten-the-dwarf. Sally sent me to him, to entice him to ambush her other paramour tonight. Roundabout ten.”
“Ah. That’s lovely. Now, as you were. Go. Go, and, my good man, do not upon pain of skewering tell anyone we spoke of this.”
So, forewarned, Mark gets his spear and his horse and two of his most omerta-respecting knights, and sets an ambush for Tristram outside Sally’s chambers. So when Tristram rides up on his horse (I’m not sure Malory visualized the action he describes here) Mark leaps out and stabs him and they joust and are both wounded and then Tristram knocks out Mark and either knocks out or kills Mark’s two men (again, Malory is vague). Bleeding, Tristram stumbles into Sally’s bedchamber and finds Sally in her foyer.