"Next fall, we voyage far from planet Earth and take off on a new adventure to a new galaxy. To a new planet. To meet up with a familiar friend."
(From the teaser trailer)
I think this movie has a different idea of story, if you compared it with some previous Barbie movies. And I'd like to share my idea about the story, as I don't find any plot of it.
Barbie starred as an astronaut girl, that exploring the space with her team. But suddenly there was damage to their spacecraft and they were forced to landed on an unknown planet.
The planet was very similar with Earth, with beautiful forest, nature, and animals. They are also meet with the residents and befriend with them. There is a hidden magic star that keeps the planet alive.
But when the evil peoples want to stole the magic star from the planet, Barbie and her team tried to protect this planet, for their familiar friend.