When I started the book I was sceptical about the "American heiress who wants to be an opera singer but is being held captive by her starchy English guardian", which seemed like a sure-fire formula for a TSTL heroine and histrionics. But Bianca was actually an engaging and interesting heroine, and I liked her desire for independence and her strength in the face of Vergil's (initial) obtuseness and everyone's pooh-poohing her ambition, even if she was a little stubborn and thoughtless on occasion.
But the blackmail mystery, and especially the melodrama around it at the end of the book, was not nearly as interesting to me. And the final scenes - oy, oy, oy! So far over the top that the book fell firmly into the non-keeper category for me.