I have almost read everything that Heather Killough-Walden has written and if I haven't read it then it is in my TBR pile. This book is a spin off series on the Big Bad Wolf series. You don't have to read the Big Bad Wolf series first, but I would recommend it because you will have a better understanding of some of the side characters and their motivations.
The vampire king is Roman D'Angelo and he has been the king for over 3,000 years. There are 12 other kings (we haven't met them all so I don't exactly know what they are kings of). The foe is revealed early on as Charles Ward who is a vampire but was good friends with the warlock king (whom Roman helped to eliminate in the last book of the Big Bad Wolf series). Roman meets Evie and wants her for his queen. I believe that the other books in the series about the kings will be about them finding their queens. They must have all been queen-less this whole time.
I didn't like that the book started out with an excerpt from the ending and then went back 3 weeks. Once I had already read that part it was almost frustrating to go to the beginning at that point, but I was drawn in quickly and was interested to read how Evie and Roman get along.
The other part that I found a little frustrating was that it seemed like Evie went straight from trying to run away from Roman to being his queen. There wasn't any time in there spent their blossoming relationship. I can see that with the timeline that there wasn't any time in which to do that, but should have been an "ah ha" moment for Evie when she should have realized that she loved him.
Overall, it was very entertaining. We got to meet the Phantom King who is the star of the next book. We met the new warlock king. We briefly met Ramses and it is hard to tell if he is a full blown bad guy or is functioning under a misunderstanding. There is so much going on in this story line it would be impossible to discuss all the side characters (so I guess you must read the Big Bad wolf series first!). I am looking forward to The Phantom King.