'Twas the Night Before Christmas (1974)

One Christmas season, the human and mouse citizens of a small town get their letters to Santa unceremoniously returned, with a message that the town has been removed from Santa's delivery itinerary because of a letter from someone in that town that insulted him by dismissing his existence. While Father Mouse confronts his cynical son Albert, the letter's writer, their human companions, a clockmaker and his family, work to regain Mr. Claus' favor.