In the latest novel in Genevieve Cogman's historical fantasy series, the fate of worlds lies in the balance. When a dragon is murdered at a peace conference, time-travelling Librarian spy Irene must solve the case to keep the balance between order, chaos...and the Library.
When Irene returns to London after a relatively straightforward book theft in Germany, Bradamant informs her that there is a top secret dragon-Fae peace conference in progress that the Library is mediating, and that the second-in-command dragon has been stabbed to death. Tasked with solving the case, Vale and Irene immediately go to 1890s Paris to start their investigation.
Once they arrive, they find evidence suggesting that the murder victim might have uncovered proof of treachery by one or more Librarians. But to ensure the peace of the conference, some Librarians are being held as hostages in the dragon and Fae courts. To save the captives, including her parents, Irene must get to the bottom of this murder--but was it a dragon, a Fae, or even a Librarian who committed the crime?
Following on the heels of The Lost Plot, Cogman's exciting fifth Invisible Library adventure finds Librarian Irene Winters, who travels through time rescuing rare and dangerous books and hiding them in the interdimensional Library, called to a version of Paris where peace talks between dragons and Fae have been interrupted by the murder of one of the principals in the dragon delegation. Also summoned to investigate is Peregrine Vale, "the nemesis of criminals across Great Britain," and rounding out the team are Mu Dan for the dragons and Lord Silver for the Fae. As keepers of the balance between the chaos generated by the Fae and the order promulgated by the dragons, the Librarians have been brought in as arbitrators, but the deceased mentioned "a mysterious book," leading some to suspect the Librarians of the murder. There are also rumors that the powerful and malevolent Blood Countess is involved, and Irene sees connections with the death that she and the dragon prince Kai investigated in The Lost Plot. Cogman ably combines sleuthing with politics, magic, and a bit of romance for a satisfying tale.