In the movie Santa Who?, Santa Claus (played by Leslie Nielsen) falls out of his sleigh and ends up with amnesia. He wanders into a small town and starts to blend in with the locals, but he has no memory of who he is or where he came from. The only person who can help him is a small child named Tommy (played by Max Morrow), who still believes in Santa Claus.
Meanwhile, a cynical newsman named Peter Albright (played by Steven Eckholdt) is tasked with doing a story on Santa Claus. However, he doesn't believe in the existence of Santa and is determined to expose him as a fraud. As he investigates Santa's background, he learns of his amnesia and starts to question his own disbelief.
As Santa tries to regain his memories, he starts to realize that he has a greater purpose in life than just delivering presents. With the help of Tommy and his hopeful Christmas spirit, Santa sets out to help the people of the small town and help them rediscover the joy of Christmas. And with the help of Peter, who eventually learns to believe, Santa is able to regain his memory and continue spreading holiday cheer.