It's a quite different setting and a quite different atmosphere from [b:Matched|7735333|Matched (Matched, #1)|Ally Condie|https://d.gr-assets.com/books/1367706191s/7735333.jpg|9631645] - the first one was set in a clean, smooth, organized and controlled Society. This one is set in the Outer Provinces - with a sense of desert, crossed by poisoned rivers. A delightful place. For WoW players, this made me think of the Hellfire Peninsula zone :P
As for the story, Ky has been sent to war by the Society; Cassia is determined to find him; and we learn more about the Rebellion^WRising. The story is told by Cassia and Ky, alternatively (changing every chapter).
I liked it less than the first one: it kind of felt like a "transition" between book 1 and what I expect to be book 3, but a bit lengthy a transition.