The Grinch, a bitter, cave-dwelling creature with a heart "two sizes too small," lives on snowy Mount Crumpet, a steep, 10,000 foot high mountain just north of Whoville, home of the merry and warm-hearted Whos. His only companion is Max, his faithful but dim dog. From his perch high atop Mount Crumpet, the Grinch can hear the noisy Christmas festivities that take place in Whoville. (The Whos of this book may or may not be the minuscule Whos of Horton Hears a Who; In the Broadway musical Seussical, the Grinch's Whos and Horton's are one and the same, the Grinch being microscopic and living on the dust speck as well. In the live-action movie, Whoville is located in a snowflake.) Envious of the Whos' happiness, he makes plans to descend on the town and, by means of serial burglary, deprive them of their Christmas presents and decorations and thus "prevent Christmas from coming". However, he learns in the end that despite his success in stealing all the Christmas presents and decorations from the Whos, Christmas comes just the same. He then realizes that Christmas is more than just gifts and presents. His heart grows three sizes larger, he returns all the presents and trimmings, and is warmly welcomed into the community of the Whos.

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