The world has changed, and now our sun's rays burn people alive with deadly abandon. Civilization survives in walled cities, nocturnal societies and underground living as people hide from the daylight with little hope of salvation. However, a crazed murderer's killing spree has revealed there are a few among them inmmune to the sun's rays. Cielo Brandt, sheltered heiress to the city's most powerful corporation, and her savior David Baxter have both survived the killer's attacks, and now they want answers. Determined to uncover the killer's mysterious origins, Cielo investigates the dark city's underground and the depths of her father's company. Meanwhile, Bax braves the postapocalyptic wasteland to hunt down another survivor resistant to the sunlight. As disturbing secrets are revealed and power struggles unfold, both Cielo and Bax must decide just where their allegiances lie.