Which opens with our heroine, Irene, stealing a book by a necromancer and, after dealing with some gargoyles and other complications, getting it back to the title library, which spans all the universes and keeps books safe.
Also, defines the Language, which you can use to make things true.
Back there, she's sent an apprentice, Kai, and sent off to collect a book from a world with both magic and tech, and on top of that, a strong chaos presence. Complications ensue. . . .
A rival librarian is also there. Fae are melodramatic. (They are forces of chaos, and in this setting, what chaos does, versus order, is force events into the patterns of stories.) Irene meets a private detective who's an earl. There are zepphlins, and a cat burglar, and a warning about an old foe of the Library, and secrets out of Kai's past, among many other twists.