Eve and her comrades land on the surface to reclaim the extinct Earth and cross paths with a survivor named Adam. Eve is then led by Adam to the last surviving city, Xion, where she meets the elder of the town Orcal and is told many stories. In order to serve her mission to save Earth, Eve develops close relationships with the key members of Xion and contributes to rebuilding the city.
On a mission to save Earth from the NA:tive, Eve is also faced with helping out the citizens of Xion. Whether you will help the survivors or not, depends purely on your decision as the player.