The Shadow Society by Marie Rutkoski
Darcy Jones has been bouncing from foster home to foster home around Chicago for most of her short life. She remembers nothing from her early childhood. She has finally managed to spend more than a year with a foster parent and finally has some friends at her high school.
Little does Darcy know that there is an alternate world just like this one as well as an alternate Chicago. But in that world, the Great Chicago Fire never happened. In that world, The Shadow Society remains a deadly threat.
When a mysterious new boy at school, Conn McCrea, captures Darcy’s attention... her heart soon follows. She is about to find out though that Conn is from that alternate world, and so is she.
Darcy is a shade. They aren’t human. They aren’t even visible much of the time, since they have the ability to "ghost" into non-physical beings. Humans fear them and the havoc they wreak on mankind. The only thing that shades fear are flames. They used to exist in our world too, but the Great Chicago fire was actually a sort of witch hunt. Now shades are only found in Conn's world.
Now Darcy has been arrested by the Interdimensional Bureau of Investigation, or IBI. Conn is an agent for this police organization that hunts down shades. Darcy is offered a chance to spy on her species' hidden organization, the Shadow Society. In exchange, she might be able to learn about the secrets of her early past that she never knew. Of course, sometimes secrets should stay secret.
Darcy must grapple with her feelings of affection and betrayal for Conn while also navigating the unfamiliar world of the shades, who have their own reasons for their destructive past. As she learns her species' ability to vanish, she becomes an excellent spy. Time is running out though. There's about to be another great fiery purge, this time led by the shades.
The Shadow Society offers action and romance in a science fiction package, while also asking us serious questions about our identity. Do others determine who we are, or do we find the answer within? Read to find out!