Unless you grew up in the Netherlands, you may not know the story of how St. Nicholas became Santa Claus and how his little-known partner helped him save Christmas.

Tune in Sunday at 9 to CBS's "Santa and Pete" and find out. (There's more lore to Christmas than you may have thought.)

And if you doubt that there's a Santa, don't mention it to James Earl Jones's 16-year-old son.

"He was late to relinquish the idea that Santa Claus exists, maybe about four years ago," said Jones. "Now I have news for him: Santa does exist. It is the spirit of a man who really did exist, Saint Nicholas."

The movie begins on a snowy Christmas Eve as Grandfather, played by Jones, recounts the legend of Santa and the partner of whom very few have heard.

It seems that 4th-century Christian bishop Nicholas, played by Hume Cronyn, is on a pilgrimage to Spain, where he is being persecuted for his religion and is falsely arrested for espionage.

Stuck in jail just before Christmas, the bishop's luck changes for the better when he meets Pete (Flex Alexander), a young Black Moor working as the prison cook. The two men become friends, and the next day Pete springs St. Nick from jail and then joins him as he goes about helping those in need. As years pass, children grow to love Pete just as much as they love St. Nick.

However, as the story continues, the pair realize that the time has come to spread the Christmas spirit to the New World. In Nieuw Amsterdam (now New York City), St. Nick and Pete face many obstacles -- for example, how does one enter a house to give gifts if all the doors are locked? -- but find help in a bunch of wandering reindeer.

As Christmas approaches, St. Nick, now known as Santa Claus, and Pete must not only keep their promise to those they've vowed to help but also to the children and families of the new frontier.

That, of course, is the plot of the movie, which is based on a book by Christopher Moore and Pamela Johnson. Tempestt Bledsoe and Emily Mae Young co-star in the movie.

Meanwhile, since making "Santa and Pete," Jones has learned more about St. Nicholas and his partner, whatever that partner's name.

"Santa always had a sidekick, on a spiritual level," he said. "If you could think of Santa as a wizard -- he was a bishop -- he had this demon that traveled with him. He would pass out the coal. Pete wasn't part of the demon force -- he was doing good things."

Native Americans had a similar legend, about a white-bearded man who flew through the air, said Jones.

Cronyn, who plays St. Nicholas, is more what Jones called a "jolly old troll, a nutty old critter" than the big-bellied guy who talks to children at shopping malls. Jones is perfectly happy to have played Grandfather, since Cronyn had to put up with wearing uncomfortable medieval-style costumes for his role, said Jones.

But Jones also said that Cronyn was one of the reasons he was happy with his part in the movie: "I'd drag my butt anywhere to work with him."