King Arthur and his knights are sitting around a table celebrating Christmas.
A Green Knight barges in and challenges King Arthur to a test.
"If any man holds himself, here in this house...that he dares to stoutly exchange one stroke for another I shall let them have...this ax"(65-69).
Sir Gawin steps up in place of King Arthur for the challenge. The Green Knight says that he can chop off his head now only if in a year he can do the same. Sir Gawin cuts off his head and the knight survives!
"Come to the Green Chapel, I charge you, and take a stroke the same as you've given..." (175-176).
"For the man who goes to battle in this green lace, as long as he keeps it around him, no man under Heaven can hurt him" (223-225).
Sir Gawin goes to the Green Chapel and the lady of the house attempts to seduce him, but he doesn't make any advances towards her. She offers Sir Gawin a sash that will save his life and he accepts.
Sir Gawin goes to meet his fate with the Green Knight, but when the night swung at his neck only a small cut was left.
"I shied once: no more. You have my word. But if my head falls to the stones it can not be restored" (262-265).
"I merely feinted, and made no mark, as was right, for you kept our pact of the first night with honor and abided by your word and held yourself true to me" (325-327).
The Green Knight then tells Sir Gawin that this was all a set up to see if he really was one of the most noble men in the land. The Green Knight was happy that Sir Gawin didn't fall for his wife's tricks and how he kept his word and showed up, so he gave him his green sash to keep.