Then did they turn again to follow the white hart, and let slip three couple of greyhounds after him; and at the last they chased him to a castle, and there they overtook and slew him, in the chief courtyard.
At that there rushed a knight forth from a chamber, with a drawn sword in his hand, and slew two of the hounds before their eyes, and chased the others from the castle, crying, "Oh, my white hart! alas, that thou art dead! for thee my sovereign lady gave to me, and evil have I kept thee; but if I live, thy death shall be dear bought." Anon he went within and armed, and came out fiercely, and met Sir Gawain face to face.
"Why have ye slain my hounds?" said Sir Gawain; "they did but after their nature: and ye had better have taken vengeance on me than on the poor dumb beasts."
"I will avenge me on thee, also," said the other, "ere thou depart this place."
Then did they fight with each other savagely and madly, till the blood ran down to their feet. But at last Sir Gawain had the better, and felled the knight of the castle to the ground. Then he cried out for mercy, and yielded to Sir Gawain, and besought him as he was a knight and gentleman to save his life. "Thou shalt die," said Sir Gawain, "for slaying my hounds."
"I will make thee all amends within my power," replied the knight.
But Sir Gawain would have no mercy, and unlaced his helm to strike his head off; and so blind was he with rage, that he saw not where a lady ran out from her chamber and fell down upon his enemy. And making a fierce blow at him, he smote off by mischance the lady's head.
"Alas!" cried Gaheris, "foully and shamefully have ye done—the shame shall never leave ye! Why give ye not your mercy unto them that ask it? a knight without mercy is without worship also."
Then Sir Gawain was sore amazed at that fair lady's death, and knew not what to do, and said to the fallen knight, "Arise, for I will give thee mercy."
"Nay, nay," said he, "I care not for thy mercy now, for thou hast slain my lady and my love—that of all earthly things I loved the best."