The world as you knew it ended. Perhaps the enemies of America detonated EMPs high over the country. Maybe a third world war erupted and nuclear missiles struck massive blows against an unprepared populace. Perhaps a force from the stars arrived and claimed Earth as its own, and took strong measures to remove humanity from the equation. It might even have been a virus, one that saw the dead rise to consume the living. Whatever the cause, the result was the same.
The infrastructure that kept the populace healthy, clean, hydrated, and fed, is obliterated. There’s no law enforcement. There are no firefighters. Hospitals and medical clinics are gone. The old, the sick, and the disabled, are on borrowed time. Medicines that kept them alive are dwindling, and the seconds toward their last heartbeat are ticking away.
The world is either/or. Either you find a way to make it, or you die.