http://en.wikipedia.org/wiki/Gears_of_warOriginally Posted by Wikipedia
Gears of War centers on the soldiers of Delta Squad as they fight to save the human inhabitants of the fictional planet Sera from a relentless subterranean enemy known as The Locust Horde. The player assumes the role of Marcus Fenix, a former prisoner and war-hardened soldier. In cooperative play, the second player plays as Fenix's friend and fellow soldier, Dominic Santiago "Dom". The two soldiers join up with Delta Squad and battle the Locust Horde through the course of the campaign.