Okay, so, five chapters, there’s a lot to cover here, but it’s boring by even Malory’s standards, which is to say, joust-heavy, so I’m going to sum up.
1) Gareth and Linet arrive at Castle Dangerous, where — I am not making this up — the Red Knight has set up a jousting field in anticipation of Gareth’s arrival.
2) In addition to all the usual jousting tournament materials, there’s a gibbet with forty executed knights on it, which Linet explains is what happens to knights who try to joust the Red Knight, and suggests one last time that Gareth give up and go home and save himself.
3) Gareth is way too knightly to do that, though, and in Arthur’s name announces his plan to deal with this ass.
4) Gareth signals his intention to joust by blowing a big wooden horn set up for that purpose, and when he hears it, the Red Knight gears up for a joust.
5) Linet points out her sister, Lionesse, peeking out from a high window in the castle, and as soon as he sees her, Gareth decides he’s in love with her. He starts giving her the eye and flirting with her over this vast distance, him being on the ground and her in a high window, and she flirts right back with winks and nods.
6) This pisses off the Red Knight, who wants to get to the joust already. The Red Knight talks trash for a bit, but Gareth isn’t moved.
7) They joust, finally, and oh, what a joust it is! Malory loves describing jousting action. He’s like Tolkien and landscapes, if Tolkien described landscapes as “and then there was a tree, and it was a big tree, and then there was another tree, and it was also a big tree,” and so on for twenty pages.
8) During the breaks Gareth goes straight back to eyeing Lionesse, and when it’s looking bad for Gareth, Lionesse weeps, which gives Gareth the strength to overcome.
9) Guess who wins? Yes. Gareth wins. The Red Knight eventually surrenders, and tells his own sad story.
10) Once upon a time, the Red Knight loved a girl, and she loved him, and then her brother was slain by either Sir Launcelot or Sir Gawaine, the Red Knight can never remember, and so she wouldn’t marry him, and that’s why the Red Knight became a villain.
11) Gareth sends the Red Knight back to Camelot to throw himself at Launcelot’s feet, which is a little ironic as Launcelot was all the time doing that to Guenever in the previous book.
12) Linet treats the wounds of both the Red Knight and Sir Gareth.
You may think that at this point Sir Gareth’s strange adventure is over, but no! We are only like halfway through, because afterwards Gareth tries to get into Castle Dangerous to woo Dame Lionesse, and despite her flirting with him and weeping for him and so on, she refuses to allow him entry.
“I’m not convinced you’re a true heroic knight worthy of my love,” she calls down to him.
“Go be a wandering knight-errant for a year, then, come back and we’ll talk.”
“I feel like this is you moving the goalposts on me,” Gareth calls up. “I defeated a bunch of knights to get here.”
“Think of your adventures up to this point as having been qualifying rounds,” she says. “Now you’re in the finals. Don’t worry, I’ll wait for you, and assuming all works out well I will be such a good wife.”
So Gareth, reluctantly, goes off by himself, whining and muttering, and he can’t sleep at all the first night, he feels so bad about it, but finally he comes to a great lodge, which is apparently Peter’s house because he’s there. Unless Peter murdered the original inhabitants and hid their bodies in the basement, I mean, who knows?