In the third instalment of the Invisible Library series, Irene and Kai are startled when a portal to the Library erupts into flames. We then discover this is not an isolated incident, but the result of a wider attack on the Library. Evil former Librarian Alberich is back, and he's on a mission to destroy the Library, recruiting allies among the Fae to help him. As Alberich wants to recruit Irene, a confrontation is inevitable. But as she battles to save the Library from complete destruction, Irene is given unexpected information about her past.