October ‘Toby’ Daye is a changeling, daughter of a fae and a mortal man. Like her mother, she able to read what has happened to a person through a mere taste of their blood. Toby is the only changeling who has earned knighthood, and she earns that position every day, undertaking assignments for her liege, Sylvester, the Duke of the Shadowed Hills.

Now Sylvester has asked her to go to the County of Tamed Lightning – otherwise known as Fremont, California – to check up on his niece, Countess January O'Leary. A baby-sitting assignment – or so it would seem; but Toby soon discovers that someone has begun murdering people close to January: if Toby can't find the killer, she may well become the next victim.