Before anyone comes bashing on me for being a horrible person for not liking a part of this series, remember this is my opinion, and I do love this series, but this book really made me like it less.
Expanded version of a review originally posted on Goodreads on January 30, 2015

Original Version

I've been reading this series for awhile now, and I loved it, but I've found that the series is starting to go downhill. I actually pre-ordered this book, expecting great things because the last book, The First Battle was phenomenal, but I really didn't like this book. It was exceedingly flat and very annoying.
To start with the characters. Cherith (one of the authors who writes under the pen name Erin Hunter) is not my favorite Erin. I think it's the way she writes her characters. For instance, in the last book Kate (another of the Erins) actually made me start to look forward to Thunder's parts in the story. I had despised his character before the last book, but in The First Battle I grew to kinda like him, but this book reestablished my hate for this character. He was arrogant and it really made me angry when he became one of the leaders. But enough about him.
Honestly, the writing was really flat, I felt that if some of the dialogue could have been improved this entire book would have improved, unfortunately that didn't happen.
However there were some redeeming qualities in this book. I loved Star Flower's character for the simple fact that she was different. I think she was the first antagonist to use seduction for her (father's) gain. I also adored the bonus story at the end. I'm really excited to see what happens when they come to the rest of the former mountain cats.
This book was flat, and some points were annoying, but I love the characters. However, I can feel my interest waning in this series, so after the final two books in this arc I'll probably quit reading it. Unless, of course, a novella or Super Edition comes out with my favorite characters in it.

Expanded Version

Where do I start with? How about Thunder> He is arrogant and really annoying. I really wish he would leave the groups already, but alas he won't because he will eventually create ThunderClan. But before I bash on him too much let me explain why I don't like him and why he reached an all time low in this book.
First off as a kit he was cute, and you felt pity for him. His mom died in an accident, his father didn't want him, but Gray Wing took him in, loved him, treated him like a son. But then he decided to leave Gray Wing for a cat who turned him away. For a cat he's heard horrible things about. For a cat who only wanted him for the assets he could bring to his group. That cat was Clear Sky, and, for the life of me, I can't see how a sensible cat like Thunder would abandon his foster-father, for a cruel cat who didn't even want him, but alas he did. Soon after, however, he realizes "my father is a jerk" so he leaves. Great timing smart one.
By now all of the cats are in awe of him as being a great fighter, look how big his paws were. Did I mention how big his paws were? It seems like every other sentence that is written about him is about how big his paws are. I really found it quite annoying. But anyways, he came back and was accepted back to the group with open... well... paws I guess. The cats are so happy he's home, he comes back great, and he even rescues a poor helpless adult cat on his way back! Great! More reason to praise Thunder!
But then there's Thunder in the last half of The First Battle. Instead of the arrogant, rude tom he used to be he seems to mature, and grow. He even grows less arrogant! Yay! But then comes the reason for this section. The Blazing Star.
Thunder goes downhill from there, folks. Seriously, though, he became so arrogant that I almost wanted to skip his chapters altogether. First off, he is supposed to be a younger cat in the group, but yet he's made a leader and nobody challenges him? What? I don't even know. Then there's Star Flower. Oh Star Flower.
I actually really liked Star Flower. She is the only cat in the series that I ca think of that has successfully seduced her way into someone's secrets. Wow, great job Erins! Your branching out from the obviously evil cats! But Thunder was so dense when he was around her, it wasn't even funny. Lightning Tail tried to warn him. But noooo, he was in love (I hope you can hear the sarcasm in that statement). Overall he took 100 steps back in this book.
Next up, one of the major parts of the book, the dialogue. Well it was bad. I don't think a cat said more than ten words to each other in the entire book. I know this is a children's/ya book, but yet this made me mad. I've read plenty of YA books with excellent dialogue and even tons of children's books that had great dialogue, but this book fell short. It didn't cut it.
But wait, this book wasn't all bad! I really liked River Ripple, he is one rad cat. Also, I really loved the fact that the Erin's did branch out and used Star Flower, and cat who uses seduction for her purposes. Also, the bonus story was great.
Overall, however, this book was just meh, it lacked the "wow factor" to make it a great book. It was simply an okay book, that, to be completely honest, I might give away, and if I don't I'll probably not read it again.