Gaslight Chronicles, book 1: Steam & Sorcery
Cindy Spencer Pape2011

Sir Merrick Hadrian hunts monsters, both human and supernatural. A Knight of the Order of the Round Table, his use of magick and the technologies of steam power have made him both respected and feared. But his considerable skills are useless in the face of his greatest challenge, guardianship of five unusual children. At a loss, Merrick enlists the aid of a governess. Miss Caroline Bristol is reluctant to work for a bachelor but she needs a position, and these former street children touch her heart. While she tends to break any mechanical device she touches, it never occurs to her that she might be something more than human. All she knows is that Merrick is the most dangerously attractive man she's ever met—and out of reach for a mere governess. When conspiracy threatens to blur the distinction between humans and monsters, Caroline and Merrick must join forces, and the fate of humanity hinges upon their combined skills of steam and sorcery...