Deep within a cave hidden in Mt. Crumpit, outside the bustling town of Whoville, lives the Grinch, a cynical creature with a heart two sizes too small. Tormented by the joy and exuberance of the holiday season, his only companion is his loyal dog, Max. The Grinch’s disdain for Christmas is rooted in a childhood spent alone and uncelebrated, a stark contrast to Whoville's passionate embrace of the holiday. As Whoville prepares for their grandest Christmas yet, the Grinch's irritation reaches new heights.

Determined to restore his peace, the Grinch concocts a plan to steal Christmas. He believes that by taking away the Whos' decorations, gifts, and feast, he'll finally be able to silence the holiday cheer that invades his solitary existence. To this end, he disguises himself as Santa Claus and employs a shoddily constructed sleigh, powered by a reluctantly enthusiastic Max. Meanwhile, Cindy Lou Who, a young resident of Whoville with an oversized heart, embarks on her own mission. She plans to trap Santa Claus on Christmas Eve, hoping to thank him for helping her hardworking single mother every year. Unbeknownst to her, her path is set to collide with the Grinch's nefarious scheme, setting the stage for a confrontation that will challenge the heart of Christmas itself.