I thought when I was watching this that Brad Bird, who directed this, had also directed "John Carter" (the interesting but incredibly messy interpretation of Edgar Rice Burroughs' John Carter of Mars). As it turns out, I was wrong about that: Andrew Stanton directed "John Carter." Stanton and Bird worked together for years at Pixar, which is probably why they got confused in my head. Nevertheless, there are a number of commonalities between "John Carter" and "Tomorrowland." The most obvious is that they're both science fiction, but it goes a great deal further: they're both about going to another world/dimension by semi-magical means (ie. based on no science we know), and they both have failed to grasp that the phrase "story arc" describes an elegant curve - instead both bumping and stumbling through their 2h10m runtimes. The idea is to introduce characters, then to build up threat and tension over the course of the movie, and resolve it as the end approaches. Obviously this isn't the only way to do a movie, but the universal use of the term "story arc" does say something. And "Tomorrowland's" plot is just a mess.
We open with the very scruffy George Clooney (as the adult Frank Walker - we meet a younger version of him later in a flashback) talking to the camera about the impending end of the world. The narrative is interrupted and eventually taken over by Britt Robertson (as Casey Newton). They were both recruited to visit "Tomorrowland," another dimension accessed by pins handed out by a very young woman ("Athena," played by Raffey Cassidy). The retro-futurist-looking "Tomorrowland" seems like a paradise to these two science nerds, but in a classic - and boring - twist, there's trouble in paradise.
I've already blown the punchline of my review at the beginning by telling you it's a mess, so I have little left to close with. And I suppose that's part of the movie's problem too - it closes weak on a heavy-handed and surprisingly uninspiring message of "dream big."