“Swear on something else. Swear on your humanity.”

I suddenly find it very hard to swallow. My humanity? With a jolt, I realize that there are far greater things at risk here than just my life. I’m in the faerie world; anything could happen. Even immortality.

The Otherworld is the home of the faeries—deceitful, decadent, and deadly. As the next in line to become Guardians, Jaye and her brother Thomas are tasked with defending the human world from all things magical. But when a routine scouting mission ends with them trapped in the Otherworld, it becomes painfully clear that someone doesn’t want them to leave the world of the faeries. Determined to not become an immortal’s pawn, Jaye kidnaps Ravven Crowe, an arrogant, solitary faerie, so that he can guide them safely home. But things quickly go from bad to worse when they are captured by the Winter Court and embroiled in a plot to start a faerie civil war. Thomas is enslaved by an Unseelie faerie, and it seems that the only way to save her brother and avoid a war is for Jaye to ally herself with Ravven.

The faeries are governed by a set of strict laws. For their own safety, the Guardians have their own rules. But with Thomas’ life hanging in the balance, there is only one way to save him that does not include breaking the faerie’s Fair Law, a crime that ends in death. Together, Jaye and Ravven must compete in a series of deadly tests given by the faerie courts in order to earn Jaye the right to be named the "Fair Assassin" and wield the Blade of Gold and Iron.

As the Fair Assassin, she will be permitted to kill any faerie she so chooses, but first, she has to live long enough. Walking a fine line between destruction and further entanglement with Crowe, Jaye is going to have to break her own rules if she wants to win. She must trust a faerie. Her life and humanity depend on it.