Bo's been mixing it up with some unsavory characters in the search for her mother, including a vampire named Siegfried. In exchange for some medical bags of blood, Siegfried leads Bo to a woman named LuAnn currently on Death Row for the murder of her stepchildren.
But when Bo and Kenzi meet with LuAnn, she's not a killer, but a mournful figure who's keeping her lips sealed. Bo thinks the woman's silence may have something to do with the fact that she's Fae, a point Bo realizes right off. Bo and Kenzi return home in a funk that only gets worse when they learn that Siegfried has been murdered.
Bo gets the autopsy report from Dyson, and since his jealousy over Bo's flirtation with Lauren has strained their goodwill, it's a tough-won prize. Bo learns that although Siegfried died in a gruesome manner, it was clearly not a suicide, and there were no struggle marks. Thinking back to the sadness in LuAnn's face, Bo realizes that there must be someone controlling Fae, making them do horrible things that they don't want to do. Bo is determined to find this person and make them pay.
But her search earns her some enemies. Someone sends a Fae assassin, called a Morag, to kill Bo. At the end of her wits, she goes to Trick for advice, who, seeing it would be pointless to try to deter Bo, gives her a weapon, called a siricon, that transforms from a simple handle to an impressive blade that protects the bearer from another's powers. It seems Bo has an ally in Trick, even though his motives remain unclear.
The Fae responsible for both Siegfried's death and the murder of LuAnn's children is a man named Vex, a favorite of the Dark Fae elders. The Ash knows that it's only a matter of time until Bo finds him and kills him, which will mean Bo's death at the hands of the Dark Fae. The Ash still has much to learn about Bo and her origins, and directs Lauren to distract Bo while Vex is ushered out of town. Bo won't listen to reason, so Lauren seduces Bo in order to keep her safe.
When Bo discovers the truth of Lauren's actions, it stokes her rage higher. She learns Vex's name from Lauren and goes on the hunt. Lauren, beside herself with grief, seeks out Dyson and tells him where she thinks Bo and Vex are. Though Vex is more powerful than Bo, her siricon allows her to master him. He tries to buy time by telling her that he has information on her mother, and she presses the siricon blade to his neck to get him to tell what he knows. Dyson arrives and Vex uses the distraction to get away.
Dyson tries to make it clear to Bo: he stopped her from killing Vex because he didn't want the Dark Fae army to end her life, but her rage at losing information on her origins only spells betrayal, and the link between her and Dyson may be permanently broken.
And across town, LuAnn's body rustles back to life - execution by lethal injection never could've killed a Fae like her - and Trick is there to gather what information he can from her.