There's definitely no sophomore slump for Michelle Zink with Guardian of the Gate! While I had a difficult time getting drawn into Prophecy of the Sisters (but ultimately enjoyed it), I was immediately hooked on this story. Perhaps that was because I was already familiar with what was going on from the first book, though I also think the action really started very quickly in this book.We see quite a bit of character development with Lia and her two friends--two of the four "keys" in the prophecy. And yes, there is betrayal that is heartbreaking and potentially detrimental to their mission, but we are left with hope in the end as well. Speaking of characters, there is just one thing that bugs me about this book, and that's the introduction of Dmitri, who I feel came out of nowhere to find a place in Lia's heart. What about James?! Is he so easily forgotten? I am definitely curious to see how that storyline evolves in the third book. Don't get me wrong--I rather like Dmitri's character, I just don't know how I feel about his place in the story.There is quite a bit more world-building in this book as well, as we follow Lia's journey to Altus and read about her time there. We've been given a few more pieces of the puzzle, yet there is still so much more to be learned about the prophecy and everyone's role in it. Overall, this was a great read that was easy to get sucked into. If you liked Prophecy of the Sisters I definitely think you will enjoy Guardian of the Gate.