I'm so conflicted about this book. I really, really enjoyed the first book in this series, Shade, as there were a lot of interesting themes and I have an interest in Irish folklore, which was an important aspect of the book. I really liked the mystery aspect of the first novel as well and the family/relationship dynamics that evolved in Shade. However, I couldn't stand about a third of Shift because it was taken up by piles of prom angst. Prom angst! I mean, really?! I get that this is a YA, but Shade was a bit more of an older/more sophisticated YA and it felt like it had regressed in the sequel. The mystery of what caused the Shift is at the crux of this series and what makes it different, and I felt like that mystery derailed for much of the novel. 
 Also, (view spoiler)[there is a very awkward scene in which Aura, the main character, gives her sort-of-boyfriend, Zachary, a hand job while there hiding in a river from evil government agents! I mean, it would have (sort of) made sense after they'd eluded the evil government agents, but while they're hiding?! That just creeped me out--and not because it's in a YA (because, duh, teenagers do that sort of thing), but because the timing made ZERO SENSE! ZERO! I mean, geez... they're evil government agents who want to capture you and do who knows what to you! Arrrrgggghh! (hide spoiler)] And, I felt like the Aura-Logan-Zachary love triangle was pushed way too far, when it felt resolved to me in the first novel. I realize, again, that this is expected for the intended audience, but it went beyond the realm of logic. 
 Finally, (view spoiler)[Aura's sort-of-not-really relationship with Dylan didn't piss me off like is has some reviews, but that had a lot to do with that I was curious about the quiet Keeley brother who always seemed to be the odd man out. What happened between Dylan and Aura also seemed somewhat plausible to me, given where both of those characters were at that point. I could have done without that story arch, but it didn't frustrate me like it did some folks. (hide spoiler)] 
 With that being said, the mystery of the Shift still has been hooked, so I'm sure that I'll read the conclusion, Shine, when it comes out next year. I'm giving it three stars, because I just can't be that mean, but it probably deserves fewer, though the story is still compelling. I did begin to really like Zachary and his smarts and good humor in this novel, and was very happy that Logan, who I couldn't stand in Shade, (view spoiler)[ finally grew up and appeared to pass on (hide spoiler)] in this book.