_Lord Sin_ is set in the late 18th century. The heroine is a young widow (26) who is essentially one of the guys: she smokes, she shoots (well), she rides aggressively, etc. Her home is treated as a men's club (and it has a name: the Top Heavy). At some point in her past, Ivo Dauntry, then the younger son of a younger son (but everyone died, so he's going to inherit the title after all) shot someone in a duel to protect her honor or something and he spent 6 years on the Continent to live the results down.
Well, he's back now, and makes a deal with George (Georgianna). He wants to be her lover, and doesn't want to be limited to one night. Antics ensue. Oh, and did I mention someone is trying to murder her?
It's well written and plausibly plotted. I just didn't find it humorous in any way; it seemed awfully angsty. This might be my fault, but there you are.
_The Duke and I_ IS funny. I failed to read it earlier because it's just so very much one of those I-have-an-attachment-disorder-and-must-b