Arin Wells has only ever wanted one thing, to take care of her family. When she ends up becoming the first person in history to beat her city's IQ test, she believes that things will finally get easier. Instead, Arin learns that her city's leader, Eira Ellis, has a secret plot to kill the Lost people who live outside of their walls with an encrypted nanobotic virus, and that she is the only one smart enough to stop it. But when someone she loves falls ill to the nanobots, Arin must decide just how involved she wants to get. While taking a train for a secret visit to her parents, Arin meets a handsome spy named Linc who brings her to meet the Lost and their Rebel army. The Rebels have their own solution for the virus: a plan to overthrow Eira and bring down the wall. Is Arin smart enough to hack her way into a virtually impenetrable system and save everyone she loves, or will she end up losing them all by trying?