I bought this for the neat premise: the first-person narrator is a princess of the realm, except she learns she isn't, she's only a decoy for the real princess who's been hiding out in a nunnery for twenty-odd years. Then all hell breaks loose.
I enjoyed the book, but didn't love it as I'd hoped I might. I think it's because I felt ever-so-slightly manipulated, which might be the result of me reading far too many books about a woman who takes on a dangerous and unusual role in her society; certain tropes reappear, such as the Dangerous Man whom she notices physically but does not trust (I sense future romance here), the beloved parental figure, the shocking events that propel her into a life of adventure. In my long-winded way, I'm saying that the book didn't surprise me enough, even when the underpinnings to the action were revealed to the heroine, because I'd suspected already that more was up than she knew. And since there were two possible romantic partners for the heroine, and she ends up with neither, I suspect conflict about that will be a driving force in the second book. Those kinds of conflicts bore me, if one character is there and dangled tantalizingly, only to be passed over in favor of another.
The worldbuilding was fairly mundane European historical (horses, monarchies, sailing ships, marked social classes) except for the underpinnings I mentioned above, which involved Secret History. The problem was, the Secret History could not operate without a fantastical element to give them superpowers. The fantastical element didn't quite work for me; it felt too far-fetched in the world as presented, and also too useful by half.
I bought the second book in the series, but am not sure if I will read it or not. I did like the heroine, who despite her role as Person Who Does Things, had flaws and misjudged things and all that. Maybe I'll give it a chance. Has anyone else read these?