They say all's fair in love and war -- well, there's nothing fair in this game of war, and no love lost.
You find yourself trapped in the Enemy Base; you are the only soldier left alive in your unit and YOU are the only one who can win this war for your side, whichever one that is.
Unfortunately, the blow on your head that rendered you unconscious and left-for-dead by the Enemy also obliterated any traces of memory, short or long term...
You have no idea who you are, what you are, where you are or what you are supposed to do.
Your first objective is to find out what you must do, and to whom.
From that point on, your grunt ass will be on the line nonstop until you win the war single-handedly, or die trying.