The plot of Mass Effect revolves around a mysterious alien commander who appears to be driven by a genocidal drive to wipe humanity from the galaxy.
Facing the grave threat of galactic eradication, the fate of the human race rests with the wits of one man trying to stop an alien renegade. Enjoy the extended Mass Effect cinematic trailer by clicking on the bottom-right corner arrow to view it full-screen.
Besides plans for an Xbox 360-exclusive Mass Effect trilogy, which BioWare claims “will cover the Xbox 360’s five-plus year cycle”, there are also plans for episodic content to be uploaded to Xbox Live that will fill in the story between each of the three games, though these episodes are not essential for understanding the story of the main games.