This one is a little too Romancey – two men are fighting over her the entire book – but otherwise it hits the bizarre secret world mash-up elements extra hard, including a SteamPunk setting.
The heroine is a female detective in Victorian London trying to make a name for herself, but insecure about being a commoner. And, of course, far too impulsive. She’s human but somehow immune to magic, and heals very quickly. Later it’s teased she may be part fairy creature. She can get advice from an all-powerful ghost wizard who haunts her, or have devices made by her (non-ghost) genius SteamPunk engineer friend.
Romance-wise, a powerful (also non-ghost) wizard is in love with her, along with her childhood friend who is now a police chief (in other words, her beaus are a rich noble and a brawny working man). She sleeps with the policeman to try to cure him of robotic were-wolfism (an old folk remedy?), but seems to prefer the sexy wizard.
The bad guy is a masterpiece of crazy mash-up: an (1)Ancient Evil banished by (2)Celtic shamen, who is trying to (3)impregnate women with demon babies using (4)robot (5)werewolfs recruited from a (6)secret nobility sex club. Take a moment to think how this begins. You’re correct if you said “she’s called in to investigate women being molested by robot werewolves”.
SteamPunk tends to handle female characters in 2 ways. One is having them smarter and stronger than any man. Yawn. The other is what this book does: she’s told what women can’t do at every turn, is treated like a fragile flower, but does all she can within those confines, including a few things a Victorian man couldn’t get away with. If you like clever oppressed women, this has got it.