While Tristram does the mad hermit thing for most of a year, some events transpire!
1) Sir Dagonet, King Arthur’s jester, visits Tintagil with some friends. While they’re out in the woods one day, watering their horses at a well, Sir Tristram runs up behind them and throws Dagonet down the well. Dagonet survives the experience. Later he goes hunting for the crazy shepherd that attacked him. He finds Tristram, who beats him up with a tree branch and runs away. Dagonet complains to King Mark. Mark doesn’t know Tristram returned to Cornwall, so he theorizes that Dagonet must have had a run-in with Sir Matto, this other knight who had a spell of madness and now lives as a crazy hermit in the woods.
2) Sir Palomides and Sir Kehydius make friends. They bond over their shared unrequited love for Isoud, and their own inability to rouse Isoud from her depressive episode. They decide to go find Tristram, whom Kehdyius at least knows is somewhere in Cornwall.
3) Palomides and Kehdyius hunt around for Tristram in the forest, but instead they find Mark, out hunting by himself. Palomides chews Mark out for driving Tristram mad, filling him in on Tristram’s being a mad hermit somewhere in the forest. Mark declares that it’s a damn shame as Tristram is such an excellent knight. Palomides challenges Mark to a joust. Mark declines, on the grounds that he left his jousting gear — spear, sword, armor — all at home. Kehdyius offers to loan Mark his gear. Mark panics and runs away. Palomides and Kehdyius give up their search. Fun fact: Kehdyius wanders off and Malory never mentions him again. Just like his sister before him! Tristram’s wife, remember?
4) Old King Meliodas of Liones, Tristram’s father, dies. Tristram’s cousin Sir Andred, whom you may remember from Book VIII, desires his crown. Andred talks his girlfriend into claiming that she’d just had an affair with Tristram and that he’d killed himself at the end of it and she buried him and everything, Tristram’s totally dead. Andred petitions Mark to grant him the estate of Liones, as the next of kin.
5) The lovely Isoud hears this story about Tristram having died in the arms of another woman, and decides to kill herself. She steals a sword from somewhere, takes it out to the garden, and stabs a plum tree, shoving the sword blade all the way through the tree trunk and out the other side. Then she goes around to the other side of the tree and prepares to run into the sword point, impaling herself. It’s a pretty elaborate suicide plan! However King Mark discovers her just before she does it, and he locks her up under a suicide watch.
6) Tristram’s clothes wear out and he’s stuck wandering around naked. As you can imagine, he loses a lot of weight and grows a lot of hair.
A giant name of Tauleas, or Sir Tauleas, had been in hiding for about seven years, Malory tells us. Tauleas feared Tristram, and the possibility that Tristram would declare himself a giant-slayer. But with Tristram dead, Tauleas figures he’s free to rampage about the countryside. During said rampage, Tauleas encounters a Cornish knight name of Sir Dinant, who inevitably becomes locked in mortal combat with him. They spar and wrestle, knight and giant, for some time, rolling around, stabbing, slicing, all that fun stuff. Tristram and some shepherds see this happening.
“He’s going to get himself killed!” cries Tristram. “We’ve got to help him!”
“Mmm, yeah, no,” say the shepherds. “We’re noncombatants.”
“Fine,” grumbles Tristram. “I’ll do it myself.” And he runs over to the melee, scoops up Sir Dinant’s sword from where it fell, and slices off Tauleas’s head with it. “See?” he says to the shepherds. “That wasn’t so hard!”