Sir Gawain was Arthur’s nephew. In English stories, he is always described as a brave, honest and loyal knight.
According to the story, King Arthur and his Round Table Knights were holding their New Year’s banquet at Camelot when a tall knight dressed in green and riding on a green horse came in, holding a huge axe in his hand. He challenged a knight to cut his head off on condition that the knight agreed to have his head cut off a year after. Gawain accepted the challenge and cut off the Green Knight’s head.. The knight picked up his head and rode away.
Soon after that, Gawain set off to look for the Green Knight to receive his cut. After going through many strange adventures, on Christmas Eve Gawain came upon a beautiful castle where he was well entertained. He agreed to stay on till New Year’s Day since he was told that the Green Knight lived nearby. The lord of the castle made an agreement with Gawain that each day he himself would go hunting, and Gawain stay in the castle, and in the evening they would exchange what they had got during the day.
For three days the lord went hunting but Gawain had to resist the temptation of the beautiful lady of the castle, who gave him one kiss on the first day, two on the second, and on the third day three kisses and a girdle which had magic power and would save his life. Each evening Gawain exchanged the kisses with his host for animals killed in the hunt; but on the third evening he kept the girdle, thinking that it would protect him when he met the Green Knight and received the cut. In this way he broke his promise.
On the New Year’s Day, Gawain was brought to the Green Knight. He bent over for the cut he had promised to accept. The Green Knight raised his axe and brought it down, but he stopped himself at the last moment, for Gawain had moved a little because of fear. The Green Knight laughed at him. Gawain got ashamed and angry and urged the Green Knight to finish his job quickly. The Green Knight lifted his axe to cut, but again held it in the air. He praised Gawain for not moving this time. The third time the Green Knight made a slight cut in Gawain’s neck. Then he explained that he was the lord of the castle in a different form, and that the cut in the neck had been made because Gawain was full of shame and threw the girdle away. But the Green Knight forgives him and gave him the girdle as a gift.