Clockwork Angel (Infernal Devices Book 1) by Cassandra Clare
Plus, I love Victorian London. Okay, I pretty much love London, period.
16-year-old Tess Gray sails to London after her aunt dies, on the ticket of her older wayward brother. But he's missing when she arrives. Instead, she's kidnapped by two odd, old, and probably magical women who tell her she's not human. She's a shapeshifter (and probably a warlock) and can change her look to resemble other people. This particular talent is quite desired by a powerful Magister. Before he can get his hands on her, however, Tess is rescued by Will.
Will is a Nephilim, one of a group of Shadowhunters who are charged with keeping the Laws between good and evil. They take Tessa in, unsure of whether she is a warlock, and one of the Downworlders (vampires, werewolves, demons and the like) or if her arrival is an omen of sorts. The Magister's interest in her is intriguing, and their discovery of strange, clockwork people (much like the clockwork angel pendant dangling from Tessa's neck) makes the Shadowhunters wonder if the threat is greater than imagined.
Steampunk and supernatural, cleverly dark and sparking with wit, CLOCKWORK ANGEL is a swirling adventure through a dark underworld. Will's infuriating charm, mixed with the host of likable Shadowhunters (all except the snooty and beautiful Jessamine), draw Tessa and the reader along on a wild ride through a side of London most never see. Definitely hooked me on the series and I'm looking forward to the next two Infernal Devices books (CLOCKWORK PRINCE and CLOCKWORK PRINCESS -- coming out March 19), and diving into the Mortal Instruments books as well.