It's been said that behind every great man there's a great woman. But then there's Mrs Santa Claus (Angela Lansbury), who's not content just to stay in the background. When left feeling undervalued by her husband, Mrs Claus sets out to prove that even Santa (Charles Durning) needs help to make Christmas run smoothly. Leaving her North Pole home behind, she heads to New York. Enchanted by the friendly folk she meets but deeply moved by their plight, she begins working her magic, helping to spread the Christmas spirit and make people's lives a little bit happier.