As a child, "The Grinch" has a very traumatic experience, which is why he hates Christmas. When he was young he was made fun of by his classmates because of his appearance, which is why he lives in his mountain cave and not in "Whoville". As all children love Christmas, he wants to get his own back by ruining it. He disguises himself as Santa Claus and goes to "Whoville" to steal all the decorations and presents he can find. However, small "Cindy Lou Who" manages get the Grinch to like Christmas.