The new minute-long TV commercial for BioShock Infinite begins with a shot of Elizabeth in the sight of an unknown assailant's gun, the crosshairs square on her neck, which also happens to have a noose draped loosely (for now) around it. She's crying, and looks as concerned as you'd expect given the circumstances. When the camera draws back, we see she's standing on a horse, which is even more concerning given how unpredictable those animals can be.
But never fear! The man with the gun is, of course, Booker DeWitt. Thankfully he doesn't accidentally fire on Elizabeth when he's aiming the thing at her, but switches his sight to a guy who looks a bit like a priest and seems to be in charge of the whole hanging business. A quick switch, and DeWitt is aiming at a beating heart inside a metal suit, owned by a creepy looking man/machine with a giant fist.
After that, we get a bit of Skyhook on Sky-Line action. Given how heavily that sort of thing has featured in the trailers, I'd guess DeWitt will travel that way a lot throughout the game. It comes in handy here, anyway, as he elects not to shoot the priest-type man from afar but zip down one of these Sky-Lines to sort things out in person. He saves Elizabeth with some kind of magic that comes from his hands (potentially as a result of substance experimentation), and she proves immediately useful by warning him of an enemy behind him and throwing him a gun.
Once DeWitt has shot the guy/thing, we see some kind of flying blimp-ship for about a second, which I presume is to create a sense of mystery.
BioShock Infinite is nearly here; it's due for PS3, 360, and PC on March 26.