My theory (as I am re-reading the entire "No Man's Land" storyline in the comics:
Batman is going to be out of action. A secondary character (John Blake) sees that Gotham City needs a Batman and attempts to fill the shoes. Bane comes in and kicks all kinds of ass in his attempts to take down Batman, including freeing all of the prisoners from Arkham Asylum (as he did in Knightfall). Bane crosses paths with John Blake and doesn't think he's a worthy opponent (much like he did when he crossed Azrael in Knightfall). Also, Bane has deduced that Bruce Wayne is Batman--possibly because of that guy who figured out Batman's ID in the last movie OR Ra's Al Ghul. Remember, Bane was once Ra's Al Ghul's chosen one after Batman refused the role.
Hear's where "No Man's Land" comes in: In the trailers, they show us the bridges to Gotham City being blown. This happened in that storyline as Gotham was cut off from the rest of the world. Everybody was fighting for control of the city, including the police. Meanwhile, Batman was nowhere to be found. Gotham was condemned after a disease outbreak (caused by Ra's Al Ghul) and an earthquake (Caused by God). I see an earthquake in the trailers--or something that makes a football field fall apart--and I suspect this is Ra's work in this movie.
Anyway, in Knightfall, Bane broke Batman. Batman's replacement (Azrael) rose up to defeat Bane. Batman's replacement turned bad and Batman had to return to take down "Az-Bats". Of course, that story took place over the course of two years.
For the movie, I think it will go like this: Bane comes in, beats down Azrael (or whoever John Blake is going to be). We find out that Ra's Al Ghul is actually behind everything. Batman comes back to take down Bane.
