After Earth is invaded and ravaged by ghostly aliens known simply as "Phantoms", humanity is reduced to living within protective dome cities. A scientist named Aki Ross desperately searches the world for spirits, which if gathered, could produce a wavelength that can nullify the phantoms forever.
While this movie is an impressive technical achievement in computer animation, especially for the time it was made, it utterly fails in delivering compelling characters and a comprehensible, engaging story. The film doesn't even remotely make use of the video game property that it is supposed to be based on, which is a shame as the Final Fantasy games have a rich history of imaginative, memorable narratives set within creative, vibrantly realized worlds.
This movie is just sci-fi schlock set in a drab, post-Apocalyptic world with dull, lifeless characters. You would do best to pass on this.