S1, E1: When a devastating flu-like virus wipes out most of the world's population, a handful of survivors are left struggling to stay alive as society falls apart around them. Abby Grant, a housewife and mother, is among those who remain, and sets out to find her 11-year-old son. Along the way she meets a variety of people spared by fate, and they must stick together if they are to survive this dangerous new world.