Set after events of Aliens and Aliens 3, players take on the role of Corporal Christopher Winter, a Colonial Marine sent in to find the legendary USS Sulaco and search for the marines that were dispatched to LV-426. However after an onslaught of xenomorphs wipes out most of his team, Winter and the Colonial Marines are forced to fight to survive in a hostile terrain. They soon find that they are not only against the elusive Xenomorphs, but also the Weyland-Yutani corporation, intent on breeding the xenomorphs for study.

In what is touted as the true sequel to James Cameron's Aliens, Colonial Marines pits players on a dark, hostile planet surrounded by the dangerous xenomorphs. As part of the elite Colonial Marines, they must not only end these threats, but find a way out - alive.