Shadows of the Soul is about an immortal human demon hunter Isabel who works for the angel Gabriel. She generally protects his abbey but is given an assignment to translate an ancient book for a descendant of a fallen angel. That's the best way I can think of to describe the book.
It throws you into the story and while there is a glossary I did find myself confused often about what different terms mean or how people and Angels and demons were related to each other.
I did like the storyline, but I didn't love it. I may read another in the series but I would have to look up the summary first.