In the fantastical world of Halloween Town, inhabited by creatures dedicated to the celebration of Halloween, lives Jack Skellington, the town's revered Pumpkin King. Disenchanted with the annual routine of frights and scares, Jack stumbles upon a portal to Christmas Town and becomes mesmerized by the joy and warmth of the Christmas spirit. With his curiosity piqued and a newfound purpose, Jack goes back to Halloween Town, filled with the desire to share his discovery with his fellow citizens.

Eager to make Christmas in his own image, Jack convinces the townsfolk to take over the holiday. Assigning tasks and roles for the preparation of a Halloween-themed Christmas, Jack's enthusiasm and leadership inspire the residents to reinterpret Christmas with a spooky twist. He appoints himself as the new Santa Claus, or "Sandy Claws" as he misinterprets it, and begins hatching a plan to deliver gifts to the children of the human world. Unbeknownst to Jack, his well-intentioned bid to infuse Christmas with Halloween flair begins to unravel as the inherent nature of the townsfolk clashes with the true essence of the holiday.