I received a copy of this book for review from the publisher. This in no way affected my review. 
 Gates of Thread and Stone follows Kai, a young woman/girl that is living in the slums with her brother, Reev. He is a bouncer and she delivers mail. Her best/only friend is Avan, a shop-owner's son. When Reev doesn't come after his shift one night, Kai is determined to find and save him; like he saved her years earlier. Joined by Avan, she embarks on a quest that will lead her discovering just who she is and her role in their world. 
 Lame, I know. But I'm having problems trying to come up with something without spoilers. Grr. So much of what happens is spoilers! There is a great many people and events talked about, with most of them being reveled at the end. Again, which makes it hard NOT to give any spoilers. 
 The book's blurb hooked me, making me think of a YA fantasy novel. Yet, this isn't quite right. At times I thought of a Sci-Fi/steampunk (which is close), yet also not quite right. About midway through, an item briefly mentioned made me rethink how I would categorize this, and gave me new insight into the world Kai lives in. 
 It also made me wonder about the relationship between Kai, Reev, and Avan. Thankfully, Kai and Reev's relationship is truly that of an older brother/younger sister. The way the point was made that they weren't really related had me wondering... Kai/Avan, on the other hand, is all muddled and confused because Kai is all muddled and confused. 
 Even as I struggle to write this review, I'm antsy to return to this world in the next book. Sometimes, the books I like/enjoy the most are the hardest for me to review. 4.5 Stars.