The Castle Sauvage, still standing today, is a paradise for a boy like Wart. More like a village than a castle, it has a moat and drawbridge and eight towers. Wart particularly likes the kennels where the Dog Boy lives. Dog Boy looks after the hounds and loves them more than people (his nose was bitten off as a child and he had been spurned by the other children ever since). One morning, Merlyn finds Wart with Dog Boy petting the hounds.
White's long, lyrical description of the Castle Sauvage draws particular attention to its age—this narrative aside highlights the historical underpinnings of Arthur's tale. The narrator's matter-of-fact treatment of Dog Boy's nose (in reality, a violent and traumatic experience) draws attention to the brutality of this idealized era—where something so violent is almost ordinary.
"I think it's about time we began lessons," Merlyn announces. It is hot, and Wart wishes he could swim in the moat instead. "I wish I were a fish" Wart moans. At which, Merlyn speaks strange words and, suddenly, Wart finds himself deep in the moat and transformed into a fish. Wart and Merlyn (also now a fish) swim along together—Merlyn teaching Wart how to swim properly.
This is the first of Wart's 'lessons' while under Merlyn's tutorage. Each of these lessons teaches Wart a specific lesson about the way to rule and will come to inform his innovative ruling methods when he becomes king.
Suddenly, a timid young roach (a type of fish) appears. He begins crying, and pleads with Merlyn to help his Mamma who has begun to swim upside down. The three find the roach's Mamma lying on her back and Merlyn swims around her, singing a strange song. Mrs. Roach suddenly rights herself and Merlyn and Wart continue on their adventure. Merlyn points out how Wart, who is acting carefree, should be as cautious here as in the forest: Merlyn is taking Wart to see the King of the Moat.
The lesson here (one of them) is that Wart should not be so accepting of his surroundings—he should not assume he is safe because there is no obvious danger. This very literal experience in the moat will hold true later in King Arthur's rule when he must learn not to trust people although they appear trustworthy.
Mr. P—the King of the Moat—is an enormous pike, almost four feet long with a face ravaged by cruelty and pride. He does not move, but simply looks at the pair with a remorseless eye. Wart does not know what to say, but Mr. P simply lectures on the power of the body and about the dominance of Might over Right. Suddenly, Mr. P declares it is time for them to leave; Wart, however, is hypnotized and does not notice the enormous mouth moving closer. On his last sentence, the pike's mouth opens wide and his large teeth gnash together. A second later, Wart is on dry land again, panting in the midday heat.
Wart's encounter with Mr. P is his first confrontation with Might .v. Right. Mr. P is a tyrannical, almost psychotic fish who is the true representation of this flawed ideology: he believes entirely in the power of the body, so much so that, although he warns Wart he could get eaten, Mr. P is unable to control the instinctive urge of the body to kill and then tries to eat Wart.