Mark David thinks he's the last human on Earth. Earth now looks like a run down place, where nobody lives. Mark is a scavenger, who is surviving, but is also dying inside from guilt. His sister, Ashley David, runs a run down casino where her and her band of survivors are barely surviving, but she is happy there. As aliens continually orbit Earth, trying to kill of the human race, Ashley is forced into a adventure to find her older brother, who could be anywhere in the world, so she can have help to kill the aliens. Mark is forced into his own adventure, meeting a girl named Chlöe, who trains him into combat to defend himself when the aliens land on Earth to kill off survivors.