I think that, along with Bowen's book earlier in the series, this is the only other one I actually had to stop several times during and take a break. Not at all because it was bad or anything, just that there was so much going on with the characters, their history and -quite frankly- some deep stuff was going on. I think that's a really good testament to how different each of these books really are.
This book features Declan Chase, an Irishman with a dark past with an obvious hatred for Lorekind, and then Regin, the loudmouth and attention loving Valkyrie. You find out in some of the earlier books (if you read them in order) that Chase and Regin have a 'past', and the journey and character transformation that Declan has to go through is astounding. Regin has always been a great character, but we get to delve in to her past and see more of the real (and vulnerable) woman that she really is.
This one, while not my favorite out of the series, is still a fantastic read and one you shouldn't pass up. Just be prepared for the emotional roller coaster this one will put you through!