Middle eastern terrorists spread a plague, kills most of the worlds population. Main protagonist is a navy seal, starts off by rescuing some women, starts to gather more people,sets up a community in california farming country. they look for more survivors in california (a lot of university student recuses) and nearby states.
Then recruits mexicans from south of the border to join their community. and repels an invasion from the middle eastern terrorists who are now trying to claim america for thier own. After they beat the invaders, they help out european and asian survivors whose lands are also being invaded by the same terrorists. Provide food to some asian countries in need of it, and also take in some refugees from those countries.