**This review may contain spoilers for the series. Do not read if you have not read the first three books in the series.**It’s been almost a week since I finished The Mistress and I feel like I have needed that time to fully process my feelings about it. I am usually a big ball of emotions after reading a Tiffany Reisz book and this was no different. I will do my best to put my feelings into words.The Mistress picks up right where the crazy cliffhanger ending of The Prince left off. Nora’s been kidnapped by Søren’s long thought dead wife and Kingsley’s sister, Marie-Laure. She’s gone off her rocker and has kidnapped Nora in an elaborate scheme to exact revenge on Søren. Nora stalls and keeps herself alive by telling Marie-Laure bedtime stories of her life with Søren, Kingsley and Wesley. Meanwhile Søren and Kingsley are working on a plan on getting Nora back in one piece.Alright let’s start with the things I didn’t like about this book. The first half of the book was pretty slow for me. Some of Nora’s stories seemed like lessons in BSDM, which seemed pointless since Marie-Laure was never going to understand their world. It wasn’t until about midway through that the stories really started to interest me. I also felt like there was a lot of diabolical posturing on Marie-Laure’s part, which made her a cartoonish villain instead of a menacing one. The appearance of Grace in the story also surprised me. I really like Grace from The Siren and from some of the short stories that are on Reisz’s website, but I didn’t really understand her purpose in this. Dear Wesley fell short of my expectations and I felt that his role in the story was so much less than what it could have been. My least favorite character was Laila. Søren’s niece is a sweet but bland addition to the party and her character’s purpose was apparent as soon as she showed up. I don’t want to give too much away but I thought her story arc was a little too convenient and contrived. Now that I’ve gotten the negative things out of the way, let me tell you about the good things in this book. After three books, I didn’t really think that these characters could surprise me anymore, but they did. After The Prince, I wanted Søren and Kingsley to be together. Nora’s great but I just felt like Søren and Kingsley belonged together in a way that I wasn’t sure that Nora and Søren did. But Tiffany Reisz managed to prove me wrong and, in The Mistress, she showed me how these three characters fit together. I feel like I finally understand Nora and Søren and what they mean to each other. There is a really touching scene between Søren and Nora near the end of the book that just killed me. I also learned a lot about Nora and Kingsley’s relationship, which added another dimension to the story. And for all of you people who have been waiting for a love scene involving Nora, Søren and Kingsley, wait no more. It’s seriously awesome. There is also a brief appearance by Michael and Griffin which was really sweet. I love those two and enjoy every scene they’re in.I know these words are inadequate. If you know me, you already know how much I love this series. The Original Sinners series is really unlike any I’ve ever read and these are characters I will not forget. While The Mistress had its faults, I thought it was a fitting end to an amazing series. I think everyone ended up where they needed to and I was happy with the outcome. Luckily, this ending is not a true ending and Ms. Reisz will be starting The Whites Years soon, which goes back to the beginning of Søren and Nora’s relationship. Thank you, Tiffany Reisz, for creating this world of strange and wonderful people and for taking me on this wild ride.*I received this book free of charge from the publisher in exchange for an honest review. This, in no way, affected my opinion or review of this book.