Onyx Kyngeston is a killer, a trained assassin, and the best swordsman in the kingdom. However, she is limited by her illegal love for the castle worker Kess. She is given the chance to be together with Kess, but only if she completes a quest to capture a feared assassin from the neighboring kingdom. But on her journey she discovers that the very same assassin she is meant to capture has a charming smile, and a sharp tongue to match Onyx's sword. She is put through hardships she never imagined, and she begins to doubt even her very mind. She is torn, should she be loyal to her kingdom? Or loyal to her heart?
In the epic conclusion to the Devil's Deal series, Freya has one final chance to discover the full potential of her own power, and to use it to restore balance in the universe - once and for all. After the destruction caused by Roisin, Ferya and Torix come to terms with their losses and mistakes... And prepare for a final battle that will change everything.