Heartless (Parasol Protectorate Series #4) by Gail Carriger

Lady Alexia Maccon, soulless, is at it again, only this time the trouble is not her fault in the fourth book of the NYT bestselling Parasol Protectorate series.

When a mad ghost threatens the queen, Alexia is on the case, following a trail that leads her deep into her husband's past. Top that off with a sister who has joined the suffragette movement (shocking!), Madame Lefoux's latest mechanical invention, and a plague of zombie porcupines, Alexia barely has time to remember she happens to be eight months pregnant.

Will Alexia manage to determine who is trying to kill Queen Victoria before it is too late? Is it the vampires again or is there a traitor lurking about in wolf's clothing? And what, exactly, has taken up residence in Lord Akeldama's second best closet?

Heartless is the fourth book of the Parasol Protectorate series: a comedy of manners set in Victorian London, full of werewolves, vampires, dirigibles, and tea-drinking.