Eleanor Price has spent her life being used by others for her magical talents. As a double practitioner of both music and mechanicals she makes exquisite music boxes meant to entice and inspire.

When one of her boxes is altered and used in the commission of a crime, it leaves her signature all over the crime scene—the fact she is the only person injured in the explosion indicates not only was her creation used but she was meant to die in the blast.

Chief Inspector Tobias York is head of the Yard's Office of Magical Crimes. The explosion at a local jeweler's points to a possible escalation of those who wished to overthrow the Guilds. He pulls a young woman from the rubble only to have her disappear into the crowd. The arrival of an anonymous letter to his office proves that this attack was only a prelude to a larger crime, and a trail that leads straight to the only witness of the explosion and a chance to foil a hit on the Guild Bank.

As the case heats up and the body count rises, York believes he may have made a mistake in placing the woman he's come to care about in the direct path of the killer.