A mismatched group of people realizes they must band together when a deadly virus begins to sweep the world.

The survivors are shocked at how quickly people resort to selfishness and violence.

A mysterious community is discovered; a government survivor is inspired to build a better society.

Conflicts and tensions threaten to destroy the community of survivors.

Problems arise when a so-called spiritual leader turns up promising peace and change.

The post-apocalyptic drama series concludes with Abby and her friends on the run from Samantha, who has formed a dangerous alliance that threatens everyone's freedom; Sarah is confronted by a face from the past, which leads her to betray her friends.