Nominally set in the Aliens comic book universe; Earth has fallen, the last survivors of marines, scientists and civilians fighting their way up to an evacuation point atop a mile high tower block.
That's not the main part of it, however. The main movie is a heist, where a group land a helicopter at the top of the same tower block, and need crack a safe half way down before the fleeing people and alien beasties catch up with them, and everyone is trying to make it out before the city gets nuked.
Working title concocted by my subconscious brain: Oceans3
Considering the last film I watched was Kung Fu Panda, I'm not entirely sure where this came from. Anyone want to fund my Kickstarter? ;)