This one really didn't do it for me. It went too far with an overly independent woman, crazy aunt, roguish hero, and jerky "right choice" man. Everything needed to be reigned in a bit because all three characters were over the top, and together it was just way too much.
Vivienne wants to be an explorer - awesome. I love an adventurous heroine. But she so snubs the way things should be that she would have been ruined and her prim and proper fiance would have jilted her long ago - I'm not sure he would have proposed to begin with. From wandering London along, to being caught coming out of a well-known rake's house unaccompanied - it just would never have been accepted.
Even the scenery was working against the story for me. The secret panels and the things that are found inside them were just way too over the top. I was engaged just enough to want to see how this could possibly end well. There's a good twist at one point that was a great aspect, but overall I was disappointed, especially after having enjoyed the second book in the series so much.