Every year at Christmastide, King Arthur holds a huge banquet for his knights and their supporters. King Arthur will not touch his food until someone performs a feat or tells a tale that inspires him, and this year is no exception. Waiting patiently while everyone feasts, Arthur is not to be disappointed. Suddenly, a huge green man rides into the hall on a giant green horse and challenges the knights to a friendly game. A knight may deal him a blow, any blow, and if the green knight survives, he will return the blow the following year. When no one rises to meet his challenge, King Arthur volunteers to avoid shame. Sir Gawain is Arthur’s best knight, and he insists on taking Arthur’s place, as it is his duty to protect the king at all costs.
The green knight bows his head, and Sir Gawain strikes it off. The green knight rises, reattaches his head, and laughs. He tells Sir Gawain to meet him at the Green Chapel one year from the date, and Sir Gawain is bound by his knightly honor to do so. The green knight leaves, and Arthur begins to eat although everyone is somewhat somber.
Sir Gawain lives the most of the following year in relative happiness, but as the holiday approaches, Sir Gawain becomes frightened and sad at his impending death. He has no thoughts of bowing out because he has given his word, though, and he rides out alone in search of the Green Chapel.
No one Sir Gawain encounters has heard of the Green Chapel. Time is running out, and Sir Gawain is cold and hungry. During a particularly bad winter storm, Sir Gawain falls to his knees and prays for shelter. Like magic, a castle appears in the distance. Sir Gawain approaches the gate and asks for shelter.
Sir Gawain is heartily received by the good King Bercilak and his wife. He tells his sad tale, and King Bercilak says the Green Chapel is not far. He welcomes Sir Gawain to stay until the fated day, rest, and enjoy the Christmas holidays as his honored guest. Sir Gawain agrees, and they strike up a friendship. King Bercilak proposes a winter game: he will go out and hunt for the next three days, and Sir Gawain will stay in bed and rest. At the end of each day, they will exchange winnings honestly.
The first day of the king’s hunt, Sir Gawain is in bed when the king’s beautiful wife comes to him in his bedroom.
Sir Gawain refuses her advances, but accepts a courtly kiss. When the king returns, he has piles of deer for Sir Gawain to feast upon. In return, Sir Gawain kisses the king.
The second day, the wife returns to Sir Gawain’s bedchamber. She is more insistent this time, but Sir Gawain fends her off. He receives another courtly kiss that he bestows upon the king in exchange for a wild boar.
The third and last day, the king’s wife will not take no for an answer. When Sir Gawain refuses her, she insists that he take a gift instead. She gives him an enchanted belt that supposedly will protect him from any blow. The offer is too tempting for Sir Gawain, so he takes the belt and hides it. At nightfall, the king returns with just one old fox for Sir Gawain, and Sir Gawain gives the king a third kiss.
Early the next morning, Sir Gawain puts on his belt and rides out to the Green Chapel with one of King Bercilak’s servants. The green knight teases Sir Gawain, and Sir Gawain insists he hurry and get it over with. The green knight lifts his giant axe twice, but does not deliver a blow. The third time the green knight swings, he gently cuts the back of Sir Gawain’s neck.
The green knight explains that he is also King Bercilak, and the first two misses were for Sir Gawain’s honesty, honor, and behavior as a guest. The cut was for taking the belt, but the green knight says he understands why Sir Gawain slipped at the end of his trial. The green knight would have done the same if the roles were reversed.
Sir Gawain is relieved to still be alive, but he is ashamed at his sullied honor. He vows to wear the green belt for the rest of his life to remind himself of his faailure. When he returns to the Round Table to tell his tale, the other knights decide they will also wear green belts as symbols of the fragility of their honor.