When the unthinkable happens, not everyone is ready. Not everyone knows what to do.

It is a very rare occasion that Abby Miller travels into the city, but an errand that can only be done in town prompts her to make it a girls' day out with her two daughters. Unfortunately, the day is far from perfect and they are in the worst place possible when nuclear war strikes … ground zero.

Lacking any survival knowledge, she finds herself in the shelter of the city's Liberty Tunnels with a group of strangers, none of which know much more than she does. The odds are against them. Panic, hunger, and sickness are rampant. The tunnels increasingly become more dangerous. With limited skills, Abby must pull it together, not only get her and the girls out of the tunnel shelter, but to survive long enough to make it home one last time.