It's a fun read.
A Little Deeper:
This tale relies more on good characters than a fully developed world. I don't doubt that there is a fully developed world behind the scenes but we don't actually see much of it. We see what is necessary for the story and not much else. That left me wanted more but not in a way that distracted from the story and that's the way it should be.
The characters are the strength here. The villain is an unrepentant power hungry captain of evil and while I generally prefer a little humanity in my villains this worked in context.
The two heroes more than worked. They were excellent.
Gavin Kinshield is descended from Ronor Kinshield who pledged to save the king and failed. Gavin has lived up to that legacy by failing to come through on many of his responsibilities, from fixing a door to preventing his family from being brutally murdered in front of his face. Worse, we ultimately find out that the murder was retaliation for Gavin's failure to complete a task he'd promised to complete. Yeah, he feels guilty a lot and that's part of what makes him work. He's a bit of a lout--crude, crass, and possessing less than delicate table manners. But at the heart of him, he's a decent guy. I don't think it is so much that he's a whore-with-a-heart-of-gold so much as it is that he's just a guy. He has strengths and weaknesses just like all of us. He downplays his strengths because his weaknesses (in his eyes at least) led to him seeing his wife cut open but he has them and they come to the fore when he's placed in a situation that requires them.
Daia Saberheart was born a noble's daughter--worse, his heir--and was promised to another noble's son. We don't get her entire backstory but we are told that she hated the fact that her life was being determined for her without her say. She kissed that life goodbye and burned a few bridges in the process not because it was a bad life but because she wanted her own life.
The question of whether one's life is to be determined for them or by them is a bit of a theme in the novel. While Daia Saberheart has her life laid out for her in a fashion that is rather typical for daughters of royalty and Gavin Kinshield has his seemingly dictated by an ancestor two centuries in the past it's all a question of who owns a life. Saberheart takes ownership of her life and the question of the novel is whether Kinshield will do the same.
It's a fun story with fun people and you'll probably enjoy it.
Edit--Just a follow up, as I read the sequel and it was also quite a fun read.