The Wart and Kay walk toward the Forest Sauvage alongside the strip of barley in Sir Ector’s fields. Eventually, they encounter a seven-foot-tall giant named Little John. Little John leads them to the camp of a man he calls Robin Wood, known to the villagers as Robin Hood. At the camp they meet Robin and his love, Maid Marian. Robin tells them that one of his men, Friar Tuck, has been kidnapped by Morgan le Fay, a woman of uncertain origin who is believed to be the queen of fairies. Le Fay has also captured one of Sir Ector’s servants, Dog Boy, and a local idiot named Wat. The Wart and Kay agree to help rescue the three men.
Robin tells the Wart and Kay that although his men will help them get to Morgan le Fay’s castle, only innocent children may enter, so the Wart and Kay will have to go on alone. Robin gives the boys a small knife, which he explains will protect them because fairies are afraid of iron. Robin warns them not to eat anything while they are in the castle, since they will be trapped there forever if they do so. As he gives them his instructions, his men drift in silently for their meal.
That night, the company regroups near the castle, and Marian, Kay, and the Wart successfully sneak past a fierce griffin, a creature with the head of a falcon, the body of a lion, and the tail of a snake. The fairies, hoping to lure in children, have made their castle out of butter, cheese, and meat, but the Wart and Kay find it nauseating. Inside the castle, the Wart and Kay find Morgan le Fay resting on a bed of lard, and Dog Boy, Friar Tuck, and Wat tied to pillars of pork. The boys rescue the prisoners by threatening Morgan le Fay with their knives.
Although the castle disappears when Morgan le Fay is defeated, the griffin remains and attacks Kay and the Wart as they escape. Robin’s men try unsuccessfully to fight the griffin off with their bows. As the griffin leaps toward the Wart, Kay shoots an arrow into its eye, and it dies. The griffin falls on the Wart, breaking his collarbone. Robin’s men present Kay with the griffin’s head. As his reward for the adventure, the Wart asks only to be able to bring Wat back to Merlyn to see if the magician can cure Wat, who is mad. Back at Sir Ector’s castle, the boys are congratulated for their adventure, and Kay is very proud.
The Wart becomes bored with recuperating from a broken collarbone and asks Merlyn to change him into an ant in one of the colonies Merlyn keeps in a glass tank. Merlyn agrees and tells the Wart to place a reed between the two nests. He then changes the Wart into an ant, and the Wart finds himself at the outskirts of one of the two nests. A sign above the entrance to the colony reads, EVERYTHING NOT FORBIDDEN IS COMPULSORY. In his head, the Wart can hear repetitive broadcasts that alternate between giving orders and directions and playing repetitive, soothing gibberish. The Wart comes across an ant who is busy arranging the corpses of two dead ants. Because the Wart is doing nothing, the ant thinks he is insane and reports him to the central command. Sarcastically, the Wart says he has merely hit his head and forgotten his identity, and the ant finds work for him. As the Wart works, he hears more and more broadcasts that prepare the nest for war with illogical arguments and religious sermons that advocate violence. Just as the two ant colonies are about to go to war, Merlyn returns the Wart to human form.
“The Sword in the Stone” is often considered to be more directed toward children than the other three books of The Once and Future King, and Kay’s quest supports this claim. Kay’s and the Wart’s adventures in the Forest Sauvage are comical, enjoyable, and filled with the typical traits of a fairy tale or a children’s story: castles, griffins, fairies, and, of course, the character of Robin Hood. White’s principle inspiration for The Once and Future King was Sir Thomas Malory’s Morte d’Arthur, a fifteenth-century prose rendition of the Arthurian legend that has become one of its most definitive interpretations. In his novel, however, White drastically departs from the characters of Malory’s creation. The episode feels like it is a lighthearted jaunt outside of the novel’s regular world that tries to delight a younger audience by combining famous characters like Robin Hood with fairy-tale elements like Morgan le Fay and the griffin.