At the request of his lords, who are concerned about Arthur's founding a royal line, Arthur marries Guinevere — against Merlin's advice. As dowery, her father Laudegreaunce gives Arthur the Round Table. Merlin gathers knights to fill as many of the 150 seats as he can. Arthur dubs two young knights, Lot's son Gawain and the bastard son of Sir Pellanor. At the wedding feast, each of the two new knights, along with Sir Pellanor, get knighty work to do.
A white hart runs into the hall, pursued by black hounds. A disgrunted knight, knocked down by the hart, seizes a hound and rides away with it. A lady appears, says the hound is hers, and asks that some knight pursue the thief. A strange knight rides in, seizes the obstreperous lady, and takes her away by force. King Arthur is pleased to be rid of her, but Merlin warns that these wrongs must be redressed if his court is to be respected. Arthur orders Gawain after the hart, Sir Tor after the knight and hound, and Sir Pellanor after the kidnaper and the kidnaped lady, The remainder of the tale treats the three knights' adventures.
Gawain comes honorably out of two encounters, impartially judging the conflict of two brothers and disinterestedly overcoming a knight who guards a waterway. But in his third fight he is not impartial: to avenge his murdered hounds he refuses mercy to the knight he overcomes. A lady throws herself over the knight to save him and Gawain accidentally cuts off her head. He will carry this shame until his death. Four knights come to avenge the lady and, in contrast to Gawain, show mercy when ladies ask it in his behalf. Gawain returns to court, and Guinevere imposes his penance.
