Twin sisters who are very different witches that are hunted by humans and demons alike. One sister is very adventurous while the other is not. When Vittoria is murdered under mysterious circumstances her sister Emilia wants vengeance and she will stop at nothing to get it, even summoning a prince of hell. This leads her down a dangerous path that has her involved with a lot of dark magic. She finds out her sister is one of several witches that have been killed recently and what they all have in common. She ends up trusting the prince of hell Wrath that she summoned to help her find the murderer and starts to have feelings for him. 

I enjoyed this book and will read the rest of the series but it's not the best I've ever read.