4 incredible stars!I loved Alex and Eve's story! ♡ Their history together was heartbreaking but I just adore both of these characters! :) In On Her Master's Secret Service, you finally find out what the heck happened to Alex and Eve and what led to their divorce. I won't give out any specifics because I don't want to spoil the story but basically when Alex was working a FBI case, Eve was hurt in the process. Neither of them were able to fully recover from the attack. Eve became obsessed with being in control and not showing emotion while Alex couldn't stop focusing on finding the man responsible. It was heartbreaking watching their marriage fall apart. "I thought he cared more about punishing the man who hurt me than he wanted to be with me." The only relationship that Alex and Eve have at the start of this book is through their D/s contract.. a contract Eve created and in which she dictates what happens between her and Alex. Let me tell you this contract is pretty cold.. no kissing, cuddling, or affection of any kind. Alex gets intel that could lead him to the man who hurt Eve. In order to get to the man, Alex and Eve have to go undercover at a wannabe kink club where Eve must pretend to be Alex's full time sub. This operation forces them to face some of the issues from their past as well as reignites their passion together"If you want to play, angel, we're going to play it my way. You want to take on the role of my slave? You better think about what that means. It means I'll have you the way I want you. I'll fuck you when I want, where I want, how I want, and I won't listen to your protests. You belong to me. Mine. You're fucking mine for however long this lasts." ***"I won't leave an inch of this gorgeous body untouched. I love this body. I loved it when you were heavier, and I still love it now. I love it scarred or perfect. I love it because this skin and bones houses your soul. There is nothing ugly about it. I don't care what he did. This is mine. Mine."Can I just say that I love sweet, controlling, possessive, caveman Alex? Overall, I would give this book 4 stars! It was fast paced, action filled, romantic at times, steamy, and there were a few huge twists in the end!Also, since I love Ian so much and his book is coming next, I thought I would throw in some of my favorite Ian lines from On Her Master's Secret Service:Ian talking about his dead wife: "'Yes. A lovely name for a lovely woman. But she was a crazy bitch.' For Ian, that was practically a term of endearment. He was a man who appreciated a righteous bitch."***Ian talking to Eve about her relationship with Alex: "No point. If you and Alex can't make it, there's no hope for a dumb shit like me. You two had it all. You were what I was aiming for."