Clockwork Angel

In Victorian-Era London, young American Tessa has come to meet with her brother in the aftermath of their aunt, her guardian. Kidnapped and tortured into awakening a "gift" she didn't even know about, she escapes into the care of a group of demon-hunters who call themselves Shadowhunters or Nephilim and claim to be the blood of angels. They promise to help her hunt down her missing brother even in the face of vampires and a group of occultists called The Pandemonium Club and their leader The Magister who wants Tessa and her gift for purposes of his own.