The plot, and the style of the author has still a lot to improve, but I am rating this book as a weak four, because I can definitely see improvement, I hope it's not too late for the series!
What is interesting is that the author's style sometimes is really nice. He can definitely write exciting, even heart-racing scenes, but then the story lapses into sleep, lulling the book into a lot of word repetition, detailing what does not need details and sweeping things aside that do need them. Sometimes, I really, really feel that the author wrote without actually deciding how the plot should continue, as if brainstorming, then when things got clearer he changed things in a heartbeat, eager to write about new ideas that could extend the story.