Determined to live a dark life in the company of the assassin who freed her from bondage, Sarai sets out on her own to settle a score with an evil sadist. Unskilled and untrained in the art of killing, the events that unfold leave her hanging precariously on the edge of death when nothing goes as planned.

Sarai's reckless choices send her on a path she knows she can never turn back from and so she presents Victor with an ultimatum: Help her become more like him and give her a fighting chance, or she'll do it alone no matter the consequences. Knowing that Sarai cannot become what she wants to be overnight, Victor begins to train her and inevitably their complicated relationship heats up.

As Arthur Hamburg's right-hand man, Willem Stephens, closes in on his crusade to destroy Sarai, she is left with the crushing realization that she may have bitten off more than she can chew. But Sarai, taking on the new and improved role of Izabel Seyfried, still has a set of deadly skills of her own that will prove to be all she needs to secure her place beside Victor.

But there is one test that Izabel must face that has the potential to destroy everything she is working so hard to achieve. One final test that will not only make her question her decision to want this dangerous life, but will make her question everything she has come to trust about Victor Faust.