Nil Series by Lynne Matson

On the mysterious island of Nil, the rules are set. You have one year. Exactly 365 days--to escape, or you die. Seventeen-year-old Charley doesn’t know the rules. She doesn’t even know where she is. The last thing she remembers is blacking out, and when she wakes up, she’s lying naked in an empty rock field. Lost and alone, Charley finds no sign of other people until she meets Thad, the gorgeous leader of a clan of teenage refugees... moreOn the mysterious island of Nil, the rules are set. You have one year. Exactly 365 days--to escape, or you die. Seventeen-year-old Charley doesn’t know the rules. She doesn’t even know where she is. The last thing she remembers is blacking out, and when she wakes up, she’s lying naked in an empty rock field. Lost and alone, Charley finds no sign of other people until she meets Thad, the gorgeous leader of a clan of teenage refugees. Soon Charley learns that leaving the island is harder than she thought . . . and so is falling in love. With Thad’s time running out, Charley realizes that to save their future, Charley must first save him. And on an island rife with dangers, their greatest threat is time. less

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... moreOn 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? less