Pure is a post-apocalyptic world with two opposing sides: the Dome, and outside of the Dome. Does this remind you of say, District One and District 12 of The Hunger Games? It's not exactly like that… but it's from the same genre of literature.
A totalitarian government controls the lives of the people in the Dome, while outside of the Dome is complete anarchy. That's right, no one would want to live in a world like this, making it a perfect example of a dystopia—it's literally the opposite of a perfect utopia. Novels like The Hunger Games, 1984, and Brave New World are examples of dystopias, and Pure fits right in with them.