Let me copy paste my review on Amazon:
That was quite a read! Me literally starting and finishing the book all in one day goes to show how I just can't put the book down!
The first thing I'll note is how considerably more conservative this second book is compared to the first book when it comes to describing Emily's and Tyler's love-making scenes. I don't mean anything negative about it, just genuinely curios since the first book was very explicit.
Next thing to note is chronologically, this book coincides with books 3-7 of the Overworld series (I may be off by a bit. I can't exactly remember which event happened in which book). So for those who haven't read those, go read those first or you'll miss out on a lot of references.
Anyways, yet another good story about the Overworld. At first, I had a lot of doubt about the story. I just thought that how could Emily's little adventure possible compare to the magnitude of Justin's world domination dilemma, considering both happen at the same time? Clearly I was wrong. Even though the demonic activity was very low profile compared to the almost Overworld civil war that Justin is preventing, it is no less Eden-threatening. Also as a bonus, it was nice to know Tyler's lineage and relatives. Although, to be honest, his real demonic name (or at least part of his truel name) was kinda a downer. I don't know, but it just doesn't sound fitting for a guy as cool as Tyler.
All in all, I'm looking forward to seeing more of Emily and Tyler and the behind-the-scenes troubles that were happening during Justin's story