Five years after the aliens released a deadly virus, those immune have taken up shelter in what was once an underground government facility. Welcome to NACS - North American Communications - facility, home to a few former employees, survivors who stumbled in from outside, and an A.I. system named PATRICIA. You are the most recent - and last - survivor to join NACS, and you are thrown into a world of fear, chaos, and political conspiracy. You are contacted by an anonymous resident to investigate these strange events.