Ken Levine and Irrational Games have been quiet.  Not any more.  Today 2K games announced the game they have been secretly working on.  BioShock Infinite.  How have they managed to keep this a secret?  We need better spy's.

Talking about how this BioShock would be different Ken Levine said, “when it came to begin work on BioShock Infinite we only had one rule: No sacred cows. This game is both true to what people love about the series and unafraid to question every assumption."

BioShock Infinite is a prequel of sorts.  It takes place in 1912 as is set in the floating city of Columbia.  You are former Pinkerton agent Booker DeWitt, sent to Columbia to find Elizabeth a woman imprisoned there since she was a child.  Together you will gain abilities to help escape the city.  Battles will take place indoors and outside and watch your step.  As the teaser trailer shows, it's a long way down.

[UPDATE] Joystiq has an excellent interview with Ken Levine that sheds some light on what to expect with BioShock Infinnite.