Cade has spent eighteen years underground, learning medicine and fearing the ruined world above. Then armed strangers invade Bunker 34 looking for his seven-year-old brother.
Forced to flee, Cade has one goal: keep Sable alive. Their best chance is Jared, a guarded survivor who knows the surface, carries too many secrets, and is becoming far too difficult for Cade to stop noticing.
But Sable is changing the world around him, someone wanted him badly enough to kill for him, and every mile west pulls them deeper into a mystery none of them fully understand.