The Year of Wonders is drawn from Sir Gawain and the Green Knight and certainly the most brilliant Arthurian verse-romance of the English Middle Ages. The Year of Wonders translates or paraphrases much of the poem, adds a great deal of material, and transposes the story from the omniscient third person to a first-person narrative.
In the body of the narrative, Sir Gawain, retired to a monastery, explains that he is writing his memoirs about what happened to him 40 years ago at Camelot and elsewhere:
Gawain is spending Christmas with King Arthur at Camelot. But before they can begin eating, the door is flung open and a huge man, with holly in one hand and an immense Viking-style axe in the other, comes down the hall on horseback. Both man and horse are entirely green. The Green Knight demands a Christmas game: he will endure an axe-blow, provided that he (if he survives!) may behead his beheader the following New Year's Day. Gawain accepts the challenge and beheads the green man, who picks up his head by the hair, mounts his horse, tells Gawain he's the Knight of the Green Chapel, which is where he's to be found, and storms out of the hall.
Gawain spends the intervening year unsuccessfully distracting himself with many pleasures, then sets out on a quest to find the Green Chapel and fulfill his chivalric duty. After weeks of adventures and hardships he prays to Mary, on Christmas Eve, for a place to properly celebrate Christmas. He immediately sees a beautiful castle, where he's generously welcomed by the lord and his very lovely lady, who are overjoyed to find that their guest is Sir Gawain himself, brilliant and famous knight of the Round Table. The Christmas celebrations are splendid, but he begins to find his big, boisterous host more and more eccentric, and the lady more and more alluring. On the 28th he tells his host he must leave right away. The host is distressed; Gawain says he must be at the Green Chapel on New Year's morning, and has no idea where it is; the host tells him it's less than two miles away; Gawain rejoices at being able to keep his rendezvous and accommodate his host.
But that evening, the lord proposes that while he goes hunting on the morrow, Gawain should stay in bed; and at the end of the day they should give each other whatever they've acquired during the day. In the course of the next three mornings Gawain fends off -- mostly -- the increasingly seductive Lady Branwen, who visits him in bed; even so, he must present to her lord first one, then two, then three kisses, in exchange for three gifts of game. Also, on the third day, Gawain is given a sash that Branwen says will make its wearer invulnerable. This he does not present to her lord.
He is guided to the Green Chapel, a mere hole in a mound, but the Green Knight shows up with his axe, makes two feints with it, then cuts the side of his neck the third time, because on the yhird day Gawain had withheld the green sash in the gift-exchange. With this the Green Knight reveals himself to be the host, bewitched and on a mission for Morgan le Fay to disgrace the Round Table by disgracing its most illustrious knight. He lauds Gawain, who nonetheless rides glumly home, ashamed at having deserved the scarring cut on his neck; but he is celebrated at Camelot for his peerless courage and steadfastness.
At the end of his memoir, Gawain, who has thought about Branwen for forty years, expresses desire to learn what's become of her.
