"Sir Gawain" is a famous medieval poem that tells the story of Sir Gawain, a noble knight of the Round Table and a nephew of King Arthur. The tale begins when a mysterious giant, known as the Green Knight, challenges the knights to a game. Gawain bravely accepts the challenge, setting off on a quest that tests his courage, honor, and chivalry. Throughout his journey, Gawain faces various trials, including a stay at the castle of Lord Bertilak, where he encounters temptations and moral dilemmas. Ultimately, the story explores themes of loyalty, integrity, and the complexities of human nature, making it a timeless classic in Arthurian literature.