The Grinch lives a solitary life inside a cave on Mount Crumpet with only his loyal dog, Max, for company. With a cave rigged with inventions and contraptions for his day-to-day needs, the Grinch only sees his neighbours in Who-ville when he runs out of food.
Each year at Christmas they disrupt his tranquil solitude with their increasingly bigger, brighter and louder celebrations. When the Whos declare they are going to make Christmas three times bigger this year, the Grinch realizes there is only one way for him to gain some peace and quiet: he must steal Christmas.
To do so, he decides he will pose as Santa Claus on Christmas Eve, even going so far as to trap a lackadaisical misfit reindeer to pull his sleigh.