Nimbus by A.C. Miller
It’s the year 2191 and the last known civilization hides behind a giant steel wall buried deep within a forest. For over eighty years, Nimbus has thrived under one rule: Separation. When a kid turns fourteen, they’re kicked outside the wall. For eleven years, they must survive before being given a chance at re-entry. It’s Nimbus’ way of keeping an identity the previous world didn’t have; it’s their way of preventing history from repeating itself.
Sam Martin has spent his first thirteen years in Nimbus, but today’s different. Today is Sam’s fourteenth birthday.
Meanwhile, Sam’s brother, Sean, was recently granted re-admittance to Nimbus after surviving his eleven years. Assigned to work as a member of the Elite Guard, Sean slowly begins to realize there’s something deeply wrong with how Nimbus works.
Outside the wall, Elise waits. Directed by Sean to find Sam when he’s sent out, Elise sits deep in the forest fending off a series of headaches that have bothered her since her first day outside. With one year left to prove her worth, Elise must teach Sam how to survive the horrors beyond the wall.
The outside is crawling with those willing to do anything to survive regardless of what it entails. Sam, Sean, and Elise must learn to cope with the darkness lurking both inside and outside the wall. If they don’t, those who hide in the shadows will win.