In a resource-starved, lawless post-apocalyptic wasteland, survivors struggle to stay alive in an underground shelter called Eden. Its leader, Kane, lives by the iron rule of “the strong prey on the weak, and only the fittest survive,” enforcing a brutal but efficient code for survival. But the arrival of Amy, a “saint” who believes wholeheartedly in the goodness of human nature and does everything she can to save everyone in danger, plunges the group into division and crisis.