Overview
The Green Lady has kidnapped Prince Rillian, son of King Caspian X. She plans to conquer Narnia from underground, using the enslaved prince as her general.
She understands that Eustace, Jill, and Puddleglum have been sent to rescue Rillian, and meets them as they head north from Narnia. She slyly directs them to the giants' castle Harfang for the Autumn Feast, and bids them explain that she salutes the giants by them; for she knows that "man-pies" are a traditional dish for this feast and that this is an easy way to get rid of her adversaries.
When the three unexpectedly turn up instead in her own domain, she attempts to lull their senses and critical thinking through hypnotic magic. She very nearly convinces them that neither Narnia nor the Earth truly exist, but Puddleglum successfully counters the illusion.
She finally uses her shapeshifting skill to transform into a gigantic green serpent, but the Prince recognizes her serpent form as the same one that killed his mother ten years earlier, and after a brief struggle, he strikes off her head.
Read more about this topic: Lady Of The Green Kirtle