HitFix.com has the synopsis for Tomorrowland, at least as it’s been circulating Hollywood as they cast the December 2014 Brad Bird film:
“A teenage girl, a genius middle-aged man (who was kicked out of Tomorrowland) and a pre-pubescent girl robot attempt to get to and unravel what happened to Tomorrowland, which exists in an alternative dimension, in order to save Earth.”
The interesting article looks at this description, Jim Hill’s speculation on what the film was about, Hollywood secrecy, misinformation and fan’s thirst for information.