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.

Three hundred years ago the quarians created the geth, a species of rudimentary AIs, to serve as an efficient source of manual labor. But the geth rebelled against their quarian masters and drove them into exile. Now the quarians wander the galaxy in a flotilla of salvaged ships, secondhand vessels, and recycled technology. Other species tend to look down on the quarians, seeing them as scavengers and condemning them for unleashing a dangerous synthetic life form on the rest of the galaxy.

The “Bring Down the Sky” downloadable content pack will be released to Xbox LIVE Marketplace on Monday, March 10 at 2 a.m. PDT, and will be available for 400 MS points. This is the first in a series of planned downloadable content that further expands the “Mass Effect” universe and continues the adventures of Commander Shepard and the Normandy crew.

“Bring Down the Sky” includes a new uncharted world that introduces the notorious and feared alien race of the Batarians. A Batarian extremist group has hijacked a mobile asteroid station in the Asgard system, setting it on a collision course with the nearby colony world of Terra Nova. Only Commander Shepard can save the millions of innocent civilians before the asteroid completes its deadly descent.

“Bring Down the Sky” contains approximately 90 minutes of heart-pounding action and a new Achievement worth 50 Gamerscore points.

Features :

• Determine the fate of mankind as you lead an elite tactical strike force as an epic galaxy-wide conflict unfolds. "Mass Effect" will take the player into new depths of an action-roleplaying game, with choice-based gameplay.
• While defending galactic peace and earning a position of respect for humanity in the community, gamers will discover that a greater conflict between organic life and artificial intelligence exists. Players' decisions and actions will serve to shape the destiny of all life in the galaxy as you become absorbed in the story that is "Mass Effect," the first game in an epic trilogy from BioWare. They will become the center of an engrossing story as they battle against alien life forms to save the galaxy from threatening armies.
• The player's decisions and actions will serve to shape the destiny of all life in the galaxy, while raising humanity to the pinnacle of galactic civilization via noble means or via tyranny.
• "Mass Effect" employs a real-time, squad based, tactical combat system. Players will be immersed in intense, challenging and exciting combat.
• In addition to the main story arc of the game, players will be able to visit a large number of uncharted, unexplored planets which are not directly tied to the main story. At any time during the campaign, a player can choose to explore one of these planets in an all-terrain rover in order to discover new alien life, resources, ruined civilizations and powerful technologies.
• "Mass Effect" features a huge cast of in-engine digital actors that you will encounter as NPCs, enemies or as party members. Each will have life-like facial and body movements, and an advanced dialogue system will give them engaging personalities.
• Players will be able to choose from a variety of stunning, photo-realistic character appearances at the start of the game, and throughout the game can increase various statistics which will have an impact on their performance during gameplay. Equipment, weapons and armor that are acquired during the course of the story will change the appearance of the characters.
• "Mass Effect" takes advantage of Xbox 360's hardware providing gamers with exciting new experiences, including photo-realistic, high definition graphics on an epic scale. As the future of gaming goes online, Xbox360 live features, including premium downloadable content and recognition of achievement will be available via the Xbox Live service.