Possession — C.J. Archer

When the ghost of a notorious killer possesses the body of an upper class youth, London's pre-eminent medium, Emily Chambers, must exorcise it before the spirit goes on a rampage. As if this isn't distraction enough, she must fight her feelings for brooding ghost, Jacob Beaufort, who doesn't like the new man in her life - the handsome and very much alive, Theodore Hyde. With reputations and lives at stake, Emily discovers that navigating the poorest suburbs of London in search of the evil spirit is almost as dangerous as finding her way in a Society that thinks "freaks" like her belong in the circus.