Story - The ultimate story is still civilization fending off the Reapers, but this chapter will deal with this Cerebus corporation and it's enigmatic leader. There are human civilizations disappearing and it's up to Shepard to investigate, it's termed as a "suicide mission" which may lead to the details of the teaser.
http://www.joystiq.com/2009/12/17/hands-on-mass-effect-2-the-first-90-minutes/With the game set to ship out on January 26, EA held one last hands-on sneak preview of Mass Effect 2 on Wednesday night in San Francisco. We were there, of course, intrigued by an invitation that promised we'd learn what something called "Project Lazarus" was -- as it turned out, it's a crucial part of the game's plot that makes an appearance in the first 20 minutes.We know that because -- save for some optimizations here and there -- we played the first hour-and-a-half of a finished Mass Effect 2, from the title screen until being politely informed that we were about to enter forbidden plot territory. Which is surprising, considering that the opening of the game, apart from being one of the most dramatic we've witnessed in recent memory, is also chockablock with pretty huge plot twists.That said, we must warn you that the preview after the break contains what some may consider MAJOR SPOILERS -- so if you want the beginning of the game and the surprises it holds to remain unrevealed until launch day, seriously ... don't read any further.