Industrial Magic (Women Of The Underworld Book 4), Kelly Armstrong

After Paige Winterbourne is ousted as leader of the American Coven of Witches, all she wants to do is hide under her duvet for a few months. Let the supernatural world manage without her, see if she cares...But fate, of course, has other plans. A murderer is on the loose - someone with superhuman skills.

When Paige learns that the killer is targeting children, she realises she has to get involved in the covert investigation. And so Paige - desperate to protect those she loves - is thrown into a world of arrogant Cabal leaders, drunken necromancers, sulky druid gods and pretentious leather-clad vampires. Luckily, she has a female werewolf and a certain renegade sorcerer on her side...