When Santa Claus gets killed in a freak accident after being startled on the rooftop of a house, it looks like Christmas is ruined. But fortunately, just before his death, the jolly, gift-giver passed the torch to ad executive Scott Calvin, who finishes the job of bestowing holiday cheer on all. When he finally reaches on the North Pole, however, Scott learns that he can't give up the job -- he's become the next Santa Claus. (THAT'S the Santa Clause!).

Scott returns home, only to find himself slowly changing into the pudgy, white-haired old man so beloved of children... and to find that everyone around him considers him utterly and completely mad.