Librarian-spy Irene finds herself in hot water. A mysterious killer is pursuing her across an alternate Victorian London while an old enemy pulls strings from afar . . . Irene thought her to-do list would be her undoing; she’s on missions for the Library and a dear friend, the detective Vale, and she’s training her new apprentice. Now someone is trying to kill her. As Irene, Kai and Vale pursue her would-be assassin, they uncover an insidious plot that could threaten Irene’s headquarters, Vale’s home and the Library itself. Someone is creating links between high-chaos worlds and Vale’s world and they will do anything to get Irene out of the way. When the allies’ investigation takes a wrong turn, they find themselves trapped deep underground, and Irene’s old enemies are closing in.