*You are a biological experiment made by Civil Security for the sole purpose of replicating the Marine's abilities.
*Outside the underground facility you are being held in, a battle is taking place between CS and the Usurpation forces.
*Air forces got overwhelmed by the Usurpation battleships. Now the aliens are easily taking over every installation by air, ignoring any land fortification.
*As a desesperate measure, you are set free by the scientist and troops inside the facility in hopes that you find safety in the middle of the battlefield and keep the valuable research intact. You are also given complete access to bypass any security protocol in the area.
*You are now going to the surface, where everyone departed a while ago to protect the remaining bases. Now is your duty to regroup and support your allies, if there are any.