Aria has been exiled from Reverie, one of the environmentally-sealed pods that protect the people in her society from the outside world. Cast into the "Death Shop," as they call the outside world, she expects to die quickly, her body unused to the disease and climate. Fortunately, she runs into Perry, an Outsider - a savage to Aria, initially - who has his own reasons for helping Aria to survive. The two form an alliance, agreeing to help each other to achieve their own goals.
With Under the Never Sky, Rossi has given her readers a stellar example of a commercial dystopia. It's got a great hook, a fast-paced plot, two protagonists you can't help but root for, and interesting world-building. Rossi has got some great stuff going on here - super-charged senses, crazy aether storms that resemble lightning storms but are way cooler (and more terrifying), a complex society on the outside and an alluring but also ominous society on the inside.
The story is told in Aria and Perry's alternating third person, past-tense perspectives. Rossi is quite good at getting the reader into both of these characters' heads without having to resort to a shift in typeface or some other cheat. Unlike many dual perspective narratives, it was easy to tell whose "story" was being told, even when both characters were occupying the same pages. The chapter headings - "Aria" or "Perry" - were almost unnecessary.
I liked that the world wasn't explained in a giant infodump, although Aria and Perry do fill each other in on certain things at points. I like being able to figure out as I go what the author has done here that is new - it assumes some intelligence on the part of the reader and is all the more exciting because the author isn't holding my hand while I read.
I can't talk about this book without talking about the romance. Under the Never Sky isn't primarily a romance, but the romantic subplot is strong and it is good. Rossi knows how to write a good love story. Aria and Perry start out pretty antagonistic toward each other, but even the densest reader will know their feelings will eventually blossom into love. And when they do, it is believable and pretty intense. Nothing is described in a whole lot of detail, but there's enough there that teenage me would have dog-eared the heck out of those pages.
There were some things I wasn't wild about. Rossi is overly fond of the "fragment as emphasis" tactic. A couple times in a novel works; a couple times in a chapter is overkill. It brought me out of the story sometimes and seemed sloppy. I still think the title is hokey, and both the US and UK versions of the cover are kind of terrible, the UK version particularly so (although neither of those things are necessarily the author's doing). Overall, though, this is a really solid book that stands out from others in its subgenre. I'm excited for the sequel (the somewhat painfully titled Through the Ever Night).