From Book 1: Hundreds of years in the future, the world hangs in a precarious balance between the last three cities on Earth: the upper city, the lower city, and the fallen city. Each location serves a purpose for the continuation of the human species as they fight a scourge of vicious man-eaters that has driven humans to near extinction. The populace within the cities have a dedicated job in protecting the last oasis of human life. Ellie, a resident of the lower city, faces the challenge every immune child must make as they reach adulthood, a decision that will change the outcome of their entire existence. Their life path has only two options: training to become a street-head, a protector of the city, or the illustrious job of transforming themselves into an elite brain-dead. The latter has the most important job of all: tempting death outside the defensive walls that encompass the cities to gather the most valuable object in this post-apocalyptic future: the cure to the virus. Will Ellie pick the common choice of becoming a street-head, allowing her to stay inside the relatively safe city walls? Or will she risk everything, including almost certain death, to become a brain-dead in exchange for a priceless prize?