The Rule of Barbie

My friend L'ren invited me over for a Barbie movie day. Yes, we're seventeen. No, we're not ashamed. We picked The Princess and the Pauper because it was my favorite as a child. That, of course, has nothing to do with the fact that one of the protagonists is named Erika. If you've never seen a Barbie movie, you probably don't expect much, but the plot's actually well drawn. That makes up for the animators' laziness. We kept seeing the same extras.
Even though the story tied together really well, I couldn't help but guess at the twists. It's been nine years since I watched it last. All I really remembered was
1. Character with my name
2. The kingdom, which seems to rely entirely on a specific empty gold mine, is saved when Princess Annelise discovers geods at the bottom. This bugged me as a child. Do you know how worthless those are? I had a whole box in my garage back in second grade.
But even with my limited memory, I knew this story already. The Prince and Pauper switch pops up a lot.

It started with the original Twain story

Mickey Mouse got in on the fun 

Pokemon didn't want to be left out

Neither did Disney Channel

A popular variant is The Princess and the Popstar.

Here's Veggie Tales

The Lizzie McGuire Movies uses this plot, though the title doesn't  tell it.

As does this Janette Rallison novel.

Barbie even did another one of these eight years after the original.

Did they really think no one would notice?

A story I see even more is A Christmas Carol.

And the inevitable Barbie movie.

Here's a good rule of thumb: If Barbie (or the Muppets) has made a movie inspired by it, then it is no longer a story, but a formula. I've heard it said that it's impossible to create a new story. Every idea you have for a plot comes from another plot. This is true. And so very, very wrong.
Let's strip The Prince and the Pauper down to its bare bones. We've got a Rags to Riches story. Let's see, who else has done that?

We've also got a Twin Swap story.

I'm sure Twain didn't pitch his book as Cinderella meets Parent Trap. But that's what it is. That doesn't mean it's bad or that he stole the idea. Ideas don't get recycled. They get smashed and twisted and blended and vaporized and reassembled again.
What about A Christmas Carol? We've got a holiday story. We've got a ghost story. We've got a change of heart story. Did anyone before Dickens think to combine those three ideas? Maybe. But he did it in a way that will never get forgotten.
The point of storytelling isn't to create something new and original. Stories have to power to make new things familiar and familiar things new. Don't stress about finding 'already done' elements in your favorite shows. Look at what they did to make them fresh and exciting.