It's party time at King Arthur's castle. All the knights are having fun. They drink, dance and laugh their teeth out. They know their world and think they have everything under control.
Until suddenly, out of nowhere, a Green Knight -green body with green beard and green clothes on a green horse- rides into the ballroom and presents them with a bizarre game:
“It's called And next year your head and it goes like this: one of you chops off my head, here and now, and thereby gives me the right to in turn chop off his head in exactly one year and one day.”
A game he cannot lose Gawain thinks and chops off the Green's head to the delight of the other knights.
But the Green Knight stands up, takes his head under his arm and says as he jumps on his horse, “Until next year Knight Gawain, I will see you at the Green Chapel!”.
Bound by his knight's word of honour, this absurd game turns out to be the beginning of a quest that challenges all of Gawain's certainties and strikes at the very core not only of his identity but even the meaning of his existence.