Pentasium is a network of towns and cities connected by tunnels and fenced walkways. The millions of inhabitants are not permitted outside the walls. There are more rules and regulations than you would be able to get your head around. You'd think it a prison. Maybe it is. But not created by the humans. It's a prison of the Savages.
Ariana is already messed up and lost in her own mind, she doesn't understand just how much worse things can get in a place that is already hell.