At sixteen, all Brin had ever known was the city. For his entire life he'd dreamed of crossing the walls that surrounded Arcadia, something no one in living memory had done.
Leaving the city was forbidden, a rule strictly enforced by the Overseers - Arcadia's self-appointed protectors.
They were told it was for their own safety.
However Brin soon discovers that the danger doesn't lay beyond the walls, but within them, and that he may hold the key to freeing the people from a hidden master