Okay, so this is a supercool world and an excellent alternate history. Worth reading for that alone! High points were Cass's friendships with the servants, and early attempts by Dominic to be a total jerk - also, bonus points for the very end, which I did not see coming. The mechanics of the twist, however, felt like a strange combination of "well, I knew *that*" and "I still don't entirely get it." 
 All in all, however, a good, quick read, and I'm definitely intrigued enough to go pick up a copy of the sequel!