But the truth is far grimmer. James and Cordelias marriage is a lie, arranged to save Cordelias reputation. James is in love with the mysterious Grace Blackthorn whose brother, Jesse, died years ago in a terrible accident. Cortana burns Cordelias hand when she touches it, while her father has grown bitter and angry. And a serial murderer is targeting the Shadowhunters of London, killing under cover of darkness, then vanishing without a trace.

Together with the Merry Thieves, Cordelia, James, and Lucie must follow the trail of the knife-wielding killer through the citys most dangerous streets. All the while, each is keeping a shocking secret: Lucie, that she plans to raise Jesse from the dead; Cordelia, that she has sworn a dangerous oath of loyalty to a mysterious power; and James, that he is being drawn further each night into the dark web of his grandfather, the arch-demon Belial. And that he himself may be the killer they seek.