Jack walked along the snowy path of the Hinterlands, Zero following behind as always. They were on their way once again to Christmas Town. Every year since he had prevented Oogie Boogie's takeover of Halloween and Christmas, Jack had helped Santa Claus deliver the presents to boys and girls all over the world. Zero enjoyed flying the sleigh so much Santa couldn't help but to allow him to continue the now-holiday tradition.
"Well, Zero. We're here."
Jack stared at the door with the Christmas tree on it. How odd that the doors to other worlds were placed so precariously and peculiarly in this forest. He looked at the rest of the doors. He recognized one with a pumpkin on it. That was this world, Halloween Town. But the others…There was one with a green leaf clump, one with a strange brown bird, one with stars. There was one with a colorful, speckled egg and one with a pink arrow's head. Jack was very intrigued.
After delivering all of the presents, Jack decided to ask Santa about the doors.
"Well, Jack," said Santa, "Those doors are probably towns just like yours and mine. Until we met all those years ago, neither of us had any idea that the other existed. The only way to figure out where those doors lead is to open them and find out."
And so Jack resolved that he would do just that.