Personally, I think the next trailer is going to have a speech by Optimus about how his team has gained new members and how humanity is threatened by his race once again. and that this time there is more that meets the eye.

Although i have seen no one write about it personally i think that Starscream goes behind Megs back however Megs must join forces with OP and Crew to defeat the invasion.

Hopefully i am wrong but who really knows except for Bay and Crew?