The Outsider: A Broken World Book 5 - A Broken World, #5

Escaping the Society's high-tech enclave the first time cost Skye both her mother and her innocence. Going back required the betrayal of Brennan and everything Skye loved. Now Skye is back on the outside. She's on the run, isolated and hunted by new horrors that threaten the entire world. The fate of humanity hinges on Skye finding Brennan, but doing so while being chased by the entire might of the enclave's military may prove too costly, even for Skye.