This a character spin off from the Fixer series.
I have read all the authors books. His last book was Duke, another character spinoff from the series and I felt was his best one until I read this book. He just keeps getting better and better.
Joan is the no nonsense, and very deadly heroine of The Fixer series. In this book we get all the back story of who and how Joan came to be. We learn about her child hood and the lost she suffered at a young age that deeply affected her. We learn about her father, a strong man, willing to do anything to protect his daughter.
We get to witness Joan's path through her first love. The betrayal of that love has deadly consequences turning Joan into a force of vengeance, and sets in motion her path of death and destruction. Trying to keep your moral compass straight while doing bad things can be a struggle.
We get to see Joan reinvent herself, or attempt to, with the ill-gotten gains from the spoils of war. Joan makes a connection that will last for years to come with a friend, teacher, and confident. Someone that had a dark past as well. It's a period when Joan learns to not only fight but enjoy it and become a last ditch hope for those that need help and nowhere to turn.
A confrontation ends that part of her life and propels her into a life of an assassin for hire until she’s forced to choose between a family of sorts and a line that she's not willing to cross. It's at this time, her darkest time, that she's given an assignment the will again change her life dramatically.
It's not a requirement to read The Fixer series first and I might even suggest reading this first to have a better understanding of Joan.