The story begins as Arthur and his court are celebrating the Christmas holidays by participating in contests, playing games, attending Mass, giving gifts to one another, and partaking in a feast. 

Queen Guinevere watches the festivities, sitting in a place of honor on a dais under an expensive canopy with silk curtains and imported tapestries. 

Sir Gawain and Sir Agravain, his brother, are seated next to her while Arthur's seat awaits him; Arthur has vowed not to feast until he hears a wondrous tale or there's been a challenge issued to one of the Knights of the Round Table. 

Suddenly, an imposing stranger appears—the Green Knight—astride a horse. This figure is at least head taller than any other knight present. He wears all green clothing with touches of gold and even his hair and beard are green; his horse is similarly splendidly dressed in all green too. He holds a strand of holly in one hand and an enormous battle-axe in the other, but he wears no armor. 

While the knights take in the view of this formidable champion, the Green Knight speaks, calling for whoever is presiding over the feast.