Synopsis on IMDB.com:

"This stop-motion animation film features characters created by Tim Burton, and while he is a producer of the film, does not direct. Danny Elfman contributes a lavish musical score and the singing voice of Jack Skellington (speaking voice by Chris Sarandon). Jack lives in Halloweentown and is in charge of turning out a top-notch scary Halloween each year, but he's bored of being the Pumpkin King and wanders into a mysterious forest with 6 holiday-themed doors. He opens the door shaped like a Christmas tree and discovers "the warmth that's coming from inside" in the fanciful Christmastown.

The Halloweentown residents discover Jack's diappearance and conduct an exhaustive search. They are relieved when he returns and intrigued when he calls a town meeting and tells the them about his discovery and the mysterious "Sandy Claws" (Edward Ivory). After a long research process into the meaning of Christmas, he declares that this year "Christmas will be ours!" He gives everyone a job to produce his own version of Christmas until Sally (Catherine O'Hara), his number 1 admirer, tells him that it will be a HUGE disaster! He does not listen and sends Halloweentown's top trick-or-treaters to kidnap Sandy Claws, beseeching them not to tell the nefarious Oogie Boogie (Ken Page) about his plan.

Sally tries to sabotage his Christmas Eve delivery by adding fog juice to the town well, and it almost works until Jack's faithful spectral dog, Zero, who happens to have a glowing nose, comes to the rescue. Sally deduces that only Sandy Claws will be able to help Jack now, and sneaks into Oogie Boogie's lair in an effort to free him.

Jack sets off on his sleigh, and spreads terror and mayhem at every house he visits. He ends up being blown up out of the sky by the terrified populous. Realizing both his mistake and his desire to be the best Pumpkin King he can be, he goes back to Halloweentown to find Sandy Claws and set Christmas right.

He surprises Oogie Boogie, frees Sally and Sandy Claws, and unravels Oogie Boogie in a decisive final showdown. Santa Claus scolds Jack about trying to take over a holiday that isn't his, and then sets about magically saving Christmas. Jack and Sally return to town just as Santa Claus flies over and offers the Halloweentownsfolk a bit of Christmas magic: their first snowfall. Jack and Sally share a tender moment, realizing they were always meant to be together."
 

View the opening sequence from the film!