When a group of well funded people decided years before to prepare for the end of civilization by building impenetrable shelters, they unknowingly left a legacy for a small band of survivors. Hordes of infected dead have swarmed across the world and destroyed civilization. Most of the world's population is dead, yet some people are determined to cling to life and are given a second chance when they learn the secrets of those shelters.

A small group of people brought together by chance have survived in a shelter on an island near the coast of South Carolina, but although they are safe, they cannot bring themselves to sit by and wait for all of civilization to die. They are forced to make the hard choices that include leaving the shelter when it is for the good of others.

Out of necessity, they make the decision to bring a father and his daughter, Tom and Molly, into their shelter. Not content to simply rescue the pair, they believe it is possible to reunite them with their family in Alabama. Driven by a feeling of moral responsibility to do more than just exist, they set out on a risky quest to accomplish the impossible by traveling through a devastated world.