Book 1, chapters 26-27

King Rience of northern Wales, all of Ireland, and "many isles", sends a message to King Arthur. He says that he's defeated eleven other kings, and then forced them all to shave off their beards. Rience then took those beards and made a mantle out of them! However, there's still a hole in the mantle, where Rience intends to sew in Arthur's beard, so now he demands that Arthur shaves for him. Arthur says a) he's too young to have a full beard yet (like seriously, how young is he?), and b) also, fuck you King Rience, you're the biggest asshole ever, so many fuck you:s, fuck you forever (it's a longer speech but this is the gist of it).

So that was chapter 26. In chapter 27, I fear we've got a bit of a continuity issue.

Merlin had previously neglected to tell Arthur about his biological family, resulting in Arthur knocking up his big sister completely unaware of the family relation (although totally aware that she was married, but whatever, that never stops anyone in this book) (also, serious cradle-robber, that big sister of his). Later on, Merlin tells Arthur that now he's gonna have an incest baby with his sister, who's fated to destroy him. In chapter 27, however, it's suddenly like Arthur hasn't heard this. Now, Merlin just tells him that there's a child born on May-day who's fated to destroy him eventually. Arthur resolutely thinks to himself that there's no kill like overkill, and in a probably Herod-inspired move gathers up every child in the realm born on this day, including his incest son Mordred, and put them all in a boat that is pushed out to sea so that they will die. Both less efficient and less humane than if he'd just had all their heads chopped off!
Obviously people are very upset about this, but most of them blame Merlin more than Arthur, which is, okay, fair enough I guess.

Anyway, the boat crashes on a shore by a castle, and all the kids die except for Mordred, who's saved by "a good man" who takes him in and raises him.

And that's the end of book one!