Excellent book. I don't know how Jennifer Estep does it, but she makes an assassin completely relatable to the common person/reader. I think it is because Gin is not goodie goodie, nor is she all evil -- she's just a woman with a talent for killing who only wants to do what is right.
At first I didn't know if I wanted to read this book as it is a prequel, but let me assure those who usually don't like a prequel that you should give this book a chance.
Often prequels show the character as a whiny or ditzy unformed character because it's before they have "come into their own". Ms Estep does not follow that failed formulae. Gin Blanco (aka the Spider) is relating the story of who essentially she is as a person in this book. She's not weak and she's not stupid -- overconfident and impatient, yes. In this story you can see how she learned to be so patient and what it cost her before she learned her lessons. You can also see why she had so many hard layers protecting her heart. Another important aspect to the overall Elemental Assassin series is seeing Gin as a touchstone for all of the people who are slowly introduced throughout the series in the various stories.
This book as well as the previous one really demonstrate Gin realizing her dream of a family and all of the things that go along with being a family. Gin's relationship with her foster brother, Finn, is explored a little bit more in this book taking what was shown in Web of Deceit and expanding it. One thing I have liked about the series is Gin is kicka$$ but through the help of friends and family, she prevails. In this book, she prevails on her own because it is what she needs to grow as a character and as a person. It leads to the confident, uncocky heroine we have grown to love in this series.