Unclean spirits

When Jayné Heller's uncle dies, an apparent murder victim, she travels to Denver to handle his affairs and plunges into a strange world populated by demon-summoning wizards known as the Invisible College. Just as there are rogue wizards, there are also those who hunt them, and Jayné soon connects with her uncle's handsome assistant Aubrey, a former Jesuit with his own bloody agenda, and Midian, a 200-year-old man laboring under a curse.