I'm conflicted about this book, because while I found it silly and even irritating at times, I stayed up way past bedtime to read it. That has to count for something.
My main issue with the book was 16-year-old Marian's age and immaturity. (And yes, she was immature, even for a 16-year-old.) Marian manages to engineer the most bizarre situations that no thinking person would ever take part in - like drugging the hero and putting him on his merry, sloppy way to Bath. I think her actions were supposed to make her cute, but I found her completely asinine. And about her age - I know it's historically accurate for a 16-year-old girl of that era to be contemplating marriage, but I'm not comfortable with that, especially when the hero is so much older.
On the other hand, I adored the hero - Gilbert Collinwood, Lord Ingraham. He's intelligent, funny, thoughtful, and wise, and he finds everything about Marian adorable. The main reason I stuck with the book until the end was because of Ingraham. I wanted him to have his own HEA (happily ever after) even if I don't think Marian was quite ready for her own. I was a bit peeved that he frequently called Marian "brat," but he meant it endearingly and well, she was a brat.
There was a subplot involving espionage, and some drama over the Wynswichs' future, but it didn't keep me interested. Marian's family was supposed to be charming and quirky, but they were really rather annoying - apparently it's a family trait.
I can't give this book a full thumbs down, though, because Lord Ingraham really is quite a marvelous hero. Kelly could have improved the book by giving us his perspective and sparing us from Marian's inanities. Glancing over Kelly's published works, I think this book is typical of her style, so Kelly fans may love this book. As for myself, though, without more Ingraham I'd be hesitant to read more.