The Yankee sets about a plan he has had for some time to travel through the countryside disguised as a peasant, and Arthur decides to join him. They cut their hair and dress in coarse garments and set off. The Yankee tries to acclimate the king to the life of a commoner gradually, bringing food to satisfy him until he can stomach peasant fare and not sitting in his presence when it is not absolutely necessary to avoid detection. A procession of nobles rides by, and the Yankee reminds the king he must stand and bow his head humbly. The king fails in his attempt to look humble, and the Yankee jumps in the way of a nobleman's whip just in time to take the lash intended for the king. Arthur is outraged, but the Yankee convinces him they must remain in character if they want to continue their adventures.
The king proves a troublesome companion for the Yankee, who is constantly forced to save him from his blunders. The king buys a dirk from a smuggler at an inn to protect himself, but the Yankee convinces him he must throw it away, as commoners are not allowed to carry weapons. The king asks why the Yankee lets him follow through on his foolish thoughts without warning him, and the Yankee replies that he doesn't know what the king is thinking. The king is taken aback by this and says Merlin is a prophet and knows such things, and he thought the Yankee was greater than Merlin. The Yankee sees his blunder and explains that he doesn't bother with Merlin's petty type of prophecy but can see all the history of the world thirteen and a half centuries into the future.
This delights Arthur, and he quizzes the Yankee on the future history of the world. Two knights-errant ride by while the Yankee is repositioning a dynamite bomb he has brought along and nearly run down the king, who shouts after them in his rage. The knights turn and charge at the king, but the Yankee runs by them shouting an even nastier insult, causing them to turn and charge after him. He scrambles up a boulder and throws the bomb down on them. They are blown to bits. Arthur is very impressed. The Yankee drills the king on acting like a peasant in preparation for entering a dwelling. The king has trouble with the idea of speaking to commoners on equal terms and having the Yankee sit in his presence, but he catches on eventually. The Yankee continues to drill the king on burdens of the spirit, but he cannot fathom the hardships of the peasant life. They come to a hut and find a woman dying of smallpox. Her husband lies dead beside her. The Yankee urges Arthur to leave the hut, but the king refuses and sets about his knightly duty to give succor to those in need.
He carries the woman's dying daughter down from a loft and places her next to her mother. Tears fall from Arthur's eyes as the woman caresses her daughter's now lifeless body, and the woman commiserates with him as a kindred spirit who has known a life of poverty. The place is under the Church's ban, and the woman speaks out against the cruelties of the Church and the king, but Arthur remains quiet. The woman tells her tragic story of how her sons were imprisoned unjustly when the lord of the manor's fruit trees planted on their farm were cut down and how the fines for the loss of their labor in harvesting the lord's grain robbed the family of their own crop. She uttered a blasphemy against the Church when she fell ill, so she and her family were excommunicated.
The Yankee's incognito trip with Arthur brings about a greater understanding in both of them. Arthur begins to understand the plight of the common man, and the Yankee begins to appreciate the truly noble aspect of chivalry. Arthur begins the section completely contemptuous of anyone without a title, and the Yankee's drilling on spiritual desperation and the psychological condition of the people does not really affect him. He starts to catch on to the spirit of the exercise when he volunteers to take the knapsack, thinking that an ignoble burden will help to stoop his kingly shoulders, but even this has only a transitory effect. The face-to-face confrontation with utter despair and spiritual disaster in the smallpox hut finally makes his people's suffering real for him.
For the Yankee, the smallpox episode enlightens him to Arthur's true magnificence. He is truly impressed with Arthur's courage and self-sacrifice in a situation with no hope of reward or glory. This is true heroism, the true value of chivalry, and the Yankee sees Arthur now as "sublimely great." He decides he wants to put up a statue of Arthur is his peasant disguise, caught in this true attitude of greatness.