A city without light … without hope. Caelin is a survivor. It’s been eleven years since a nuclear disaster drove much of the population underground. Caelin and her young sister Mardy were left topside, where Caelin uses salvage to trade for shelter. Until she gets hurt. To save her life, a handsome stranger named Jate brings the sisters to rebel turf where plans are being hatched to conquer the Undercity. The rebels preach good life for the masses, and both Caelin and Mardy are hooked on the dream. But as Caelin is drawn deeper into the rebel’s inner circle, passion ignites between Caelin and Jate, and he suddenly seems determined to push her away. Then she discovers the harsh price of loyalty. The rebel’s dream becomes a nightmare that puts her sister on a dangerous mission to the Undercity. Caelin must determine who to trust before Mardy and the population of the Undercity are wiped out.

Paradise isn’t all it’s cracked up to be. Everything should be perfect in the Undercity, where Caelin and her younger sister Mardy are safe from the radiation topside. But safety feels more like prison. The Undercitizens aren’t exactly welcoming, and Lucio and his Impartialists continue to pound the city’s barrier, more scavs flocking to their army every day. Then Mardy goes behind Caelin’s back to accept a government assignment to spy on the Impartialists. In spite of the danger, Caelin goes after her. Once more in the camp of the man who killed her best friend, Caelin must convince Lucio of a loyalty she’s renounced in order to bring Mardy home. It doesn’t help that Lucio suspects Caelin still has feelings for Jate, the special forces officer who betrayed him, or that Lucio’s suspicions are right. As her cover story unravels, Caelin discovers Lucio’s true plan for taking over the Undercity. Her desperate attempt to protect Mardy backfires, and Jate is caught in the crossfire of Lucio’s revenge. Caelin can’t rescue the man she loves without abandoning Mardy to the Impartialists. How will she live with herself if she makes the wrong choice?

Young Mardy arrives in Dupont Shelter when her sister nearly dies from radiation exposure. While Mardy waits for her sister to recover, the leader of a rebellion begins teaching Mardy the ideals of the Impartialists. This path leads to her unquestioning obedience and instills a belief in Mardy that the end justifies the means.