I can't say much about the plot of this one - as it is the culmination of a trilogy. The sisters' stories started a long time ago and this book brings it all to a head. 

I'm obsessed with this trilogy. I honestly think it's some of the best fantasy I've ever read. Highly, highly recommend. 

I do want to add that this series is NOT Young Adult. It is full of violence, religious fanaticism, emotional and physical abuse, and some sexual content. I've it listed that way in some places and I highly disagree. Please check trigger warnings!