This book is honestly amazing. It is a YA novel- NOT a teen novel. You do not want to buy this novel for people under 12 because, in places, there is quite a fair bit of violence which even as a 20 year old made me feel slightly uncomfortable- which is great writing from Reilly, because it really is a special kind of YA novel. The teenagers feel like teenagers, something many writers seem unable to do. I love dystopian and apocalypse novels but this is an amazing twist on a genre that can often be done badly. Skye was a really loveable character, as was Red, Bo and Jenny. Everything about the twists and turns of this novel is something you don't see in YA novels often enough. Its adult writing for YA which just doesn't happen. I cannot rate this novel highly enough. The cover is amazing and eye catching, it's worth a read. If there was to be any criticism, it would be that I would have wanted to learn more about the tunnel, the symbols and the other gems- but it's understandable that Reilly didn't put this in because it would have ruined the fast pacing that occurs the last 1/4 of the book. All opinions in this review are my own opinion but I would like to thank Hot Key Books for an advanced copy of this novel.