I feel a bit like a broken record, but I love the setting of this series. While I loved the world of Shadowhunters and Downworlders created in the Mortal Instruments series, take that whole world and moving it to Victorian England somehow makes it seem more "real." The history of the familys before the chaos of the divisions of the shadowhunters worlds. 
 In addition, I love being able to journey with Tessa as she finds out more about herself and her heart.