The Green Knight comes to King Arthur's court, and he is invited to stay, but the Green Knight refuses the invitation.
The Green Knight started to taunt Arthur's men, saying that they are afraid. Arthur, confused, is about to take an attempt before Gawain stops him, and he does it himself.
Gawain leaves for his quest, and he stays at a king and queen's castle. There the queen tried to seduce Gawain while the King was away hunting, and, but he resisted. On the third day Gawain accepted the gift of her scarf, but doesn't tell the King.
"And greeted him nobly, for nothing on earth frightened him. And he said to him, “Sir, you are welcome in this place; I am the head of this court. They call me Arthur. Get down from your horse, I beg you, and join us for dinner," (Lines 32-35)
On New Year's Day Gawain goes to the Green Chapel to confront the Green Knight, and he starts making fun of Gawain who's trembling, so he promises that it'll be the last time he flinches.
"You shiver and blanch before a blow's been shown!" (Line 94)
The Green Knight who is happy to strike down on Gawain gives him a hard blow to the neck, but it barely makes a nick, but then Gawain challenges him to a real fight which the Green Knight says no.
"The lord of the castle welcomes Gawain and invites him to stay with him and his lady for a few days." (page 237) "And Gawain did, and she gave him the gift with great pleasure," (line 233)
The Green Knight tells Gawain he was the king, and he was the one who sent his wife to seduce him, and he he even knows about the scarf. He also thinks Gawain is the most honorable knight he's ever met so he invites him to stay, but Gawain declines and returns to Camelot.
"Said Gawain, “I shied once: No more. You have my word." (lines 261-262)
"It hurt him no more than to nick the nape of his neck, so it split the skin" (Lines 291-292). "I'll repay you at once with all the force and fire I've got" (Lines 304-305).
"I consider you polished as white and as perfectly clean as if you had never fallen since first you were born" (Lines 370-371) "And so they embraced and kissed and commended each other" (Line 387).