I really liked the book overall, but there were a few areas of weakness that I feel I need to point out.
First though I would like to say that the great things about this book are Cassie and Grey. I absolutely adored the both of them. If I had to give stars based on the main characters this book would have gotten a resounding 5 stars for me. Cassie is probably one of the strongest female characters I've ever read in a historical romance novel. Grey's a true flawed hero, who learns from his mistakes and at times, he made me want to cry because he makes himself so vulnerable to Cassie and vice-versa. Both of them are written beautifully and I definitely felt the vulnerability, heat and romance of the pair. I felt their connection from the first and I really liked how Putney developed their romance.
The story itself was quite well-done, as I said above I really liked the book overall. Grey is imprisoned by a cruel and deranged French government official and Cassie is sent to find information on his disappearance and ends up rescuing him. I loved the aspect of the reverse 'damsel in distress' here, or I should say 'Gentleman in distress'. I love that she was so clever a spy that she managed to rescue Grey and Pere Laurent. This gets a big thumbs up from me. I also loved the addition of Regine and her puppies and that Grey rescued Regine and showed a sensitivity few male heroes exhibit in historical romance novels.
And here we come to the not-so-good.
1) Cassie's explanation of why she never contacted her relatives in England. She basically tells her cousins that she didn't think they would remember her after all those years. She had played with those cousins and been around the British side of the family when she was a child. I'm pretty sure that even at 17/18, when she came back to Britain after about five years of being away, they would have remembered her and not thought her an imposter, especially because of her distinctly red hair which is a family trait from the British side of her family. Plus, she was very much loved by the family and she adored them in turn, so it really puzzled me that she chose to basically ignore her family for 12 years and just become a spy in order to survive.
2) The resolution between Grey and his captor.
Major Spoiler: please don't read on if you don't want to know how Grey's kidnapping storyline in France is resolved:
Grey kills his tormentor; a French government official, who is quite high up in the government. To clarify, Grey has to go back to France, after his escape, because Pere Laurent and his family (who helped Grey and Cassie as well) have been captured and taken to the dungeon by the official. This was an obvious plot point and I knew this was going to happen from the beginning, but it actually didn't bother me that much. But I digress. Consequently, the soldiers serving under him get ready to kill Grey. This makes sense as an Englishman, the enemy, just killed a high French official. But then, the French official's wife (and the reason Grey was in the dungeon for 10 years) comes in and stops the soldiers from killing Grey by saying it was self-defence on Grey's part. That may well have been true, but it wouldn't have mattered all that much, given the two countries were at war and saw each other as enemies. Even if Grey would not have been killed by the soldiers right away, at the very least they would have arrested him. But after the interference, nothing happened, the soldiers just let everyone go as if nothing had happened. This, I found not believable.
3)The French government official imprisoning Grey for 10 years without a ransom demand. I get the official wanted to make him suffer, but I think he would have either killed him, especially after Grey attacked him in the dungeon once, instead of having him in his dungeon for 10 years. More likely, he would have sent a ransom demand to Grey's family, despite the fact that Grey said his family wouldn't care to pay it. Grey is the heir, even if the family didn't like him, they would have still paid to get him back. The French official liked power, possesions and luxuries, and the money he would have gotten as ransom, would have enabled him to become even more powerful, so I simply didn't understand why he wouldn't at least try. That didn't make sense.
So that's it; the great, the good and the not-so-good. Overall, I'm very satisfied with this read and would recommend it.