This has been a recommended read if you're a fan of the Graceling series or of The Red Queen. Here's what our catalog description provides as a summary: "Orphaned by the Border Wars, Alina Starkov is taken from obscurity and her only friend, Mal, to become the protege of the mysterious Darkling, who trains her to join the magical elite in the belief that she is the Sun Summoner, who can destroy the monsters of the Fold."
Strange and deadly monsters? Check! Dark magic? Check! Manipulation and revenge? Check! Still not convinced? Take a look at the trailer:
This is the first in a trilogy--the next two are Siege and Storm and Ruin and Rising. You can read about all three books, and the author herself along with all of her other books, at the Grisha Trilogy website.