Well, back up. Mary Challoner wasn't the desired object. Her flighty, greedy, ill-mannered sister Sophia enticed Dominic to arrange an assignation (Sophia thinks that will force him to marry her, Dominic thinks otherwise since she's behaving like a trollop). Mary steals away on the carriage in Sophia's place - to save the family character, so to speak - and winds up under Dominic's protection. And he intends to marry her...but Mary is rather wary of the whole heir-to-the-Duke-of-Avon thing.
The plot of this novel is more complicated than that of These Old Shades. There are more characters, old and new, and more complications so instead of a nice straight road there are more than a few switchbacks. I literally could NOT put it down, though, even when the plotting got a little crazy. In the penultimate chapter, when Mr. Comyn started explaining what happened in Dijon, and Rupert kept interrupting, I was ready to shake the book until it's teeth rattled. Like a person. Oy.
(view spoiler)My favorite scene in the entire book is the one where Mary pours out the whole story and all her concerns to the "noble gentleman" who comes to her assistance in the wilds of France...he turns out to be the Duke of Avon and lays all her fears to rest. It was a really nice section of dialogue. Related to this, I found it interesting that had Sophia gone with Dominic as planned, in no way would the family have allowed Dominic to marry her - a scheming little brat. Avon would have let her rot. But once it was established that Mary was sensible - and could "handle" Dominic, which I suppose shooting him in the arm and tossing a pitcher of water on him demonstrates - Avon had no compunction regardng Dominic's marriage with her. Sort of a double-standard since they both have the same grandfather who is acquainted with Avon...I guess the thought would be that while Sophia obviously got the mother's vulgarity, Mary got the Challoner gentility through her father's bloodline - very Pride and Prejudice (Jane/Lizzy vs. Kitty/Lydia).
Next up: Regency Buck (I was going to read An Infamous Army next, but it turns out that half the hero/heroine couple are got out of Regency Buck so I'll have to pick that one up next instead)