Mass Effect is the first in a trilogy of games with an overarching story. As the first human Specter – sworn defenders of galactic peace – your mission is to halt the advancing armies of a legendary agent gone rogue. But as you lead your elite team across hostile alien worlds, you will discover the true threat is far greater than anyone imagined.This Bonus Disc features exclusive content for those who pre-ordered the game at select retailers. Included are a short documentary introducing the game, two unique sets of gamer pics (6 total), two unique Xbox 360 themes with four images each, four historical Mass Effect trailers (from X05 and E3 2007), and demos and bonus videos a playable demo of Blue Dragon and videos of Lost Odyssey, Halo 3 and Halo Wars.