In a kingdom full of legends and magic, a young knight named Gawain, nephew of King Arthur, embarks on an adventure that will test him in ways he never imagined. It all begins on Christmas Eve when a mysterious green-skinned knight appears, challenging the nobles of the court to a deadly game: whoever beheads him must seek him out a year later to receive the same in return. Without a second thought, Gawain leaps into action and cuts off the stranger's head, only to discover that he stands up, picks up his head, and leaves, leaving Gawain with a countdown to his fate.