The Clockwork Scarab - Stoker and Holmes, #1

Evaline Stoker and Mina Holmes never meant to get into the family business. But when you're the sister of Bram and the niece of Sherlock, vampire hunting and mystery solving are in your blood. And when two society girls go missing, there's no one more qualified to investigate. Now fierce Evaline and logical Mina must resolve their rivalry, navigate the advances of not just one but three mysterious gentlemen, and solve a murder with only one clue: the strange Egyptian scarab.
The stakes are high. If Stoker and Holmes don't unravel why the belles of London society are in such danger, they'll become the next victims...