Terminator: Salvation story?

I watched the trailer, and its begins with the machines on the upper end of the battle, big surprise... but what is the story? Bale seems decant, and I am very hesitant about McG, another case with Charlie Angels involving the question, what the h*ll is the plot? I expected to see more machines in the new trailer if the machines are supposedly winning, like beginning of Terminator 2 style. The setting is a barren wasteland, I was expecting to see much more machines in the trailer. A PG-13 raring would be ironic since this part of the film is the actual war.