This is the "Arkham Asylum 2" everyone was talking about. It's been named, and it's set in Arkham City. Hey, wait a second - that isn't where Batman lives. What gives?
According to the press release, it's "the new maximum security 'home' for all of Gotham City's thugs, gangsters and insane criminal masterminds." Let me guess: they break out. Wait, wait: they proceed to take control of the facility. Oh and then! Batman has to fight them. I should point out that this is just wild, rampant speculation on my part, of course. Oh, and Commissioner Gordon will probably be there.
You can find the game's announcement trailer from a little while back on the official site .