Nil Unlocked (Nil Series, 2)

Nil Unlocked (Nil Series, 2) by Matson, Lynne. hardcover edition. ISBN: 9781627792936.

On the island of Nil, the rules are set. You have exactly 365 days to escape―or you die. Rives is now the undisputed Leader of Nil City, but keeping the City united is tougher than ever. Raiders have grown bolder, supplies are dwindling, and non-human inhabitants have taken a turn toward the deadly. New arrivals cause rifts within the City, putting the Search system at risk, and calling everything Rives knows into question. Desperate for answers, he teams up with the only other person searching for them: Skye, a new arrival with a mysterious past of her own. Soon the duo find themselves locked in a desperate race to save all the residents of Nil―and possibly destroy the island forever. But at what cost? And who will pay the price?