Irene is an agent of the Library, a place that exists outside normal space and time. In fact, as long as the agents and librarians that work for the Library are there, they do not age in the slightest. Only when they are out in the different worlds of the multiverse, do they visibly age, and how much depends how time passes in the various worlds they find themselves. As an agent of the Library, Irene is sent to retrieve books that are deemed of value, because they are represent something different from what already exists in the archives. Sometimes she has to disguise herself and go undercover for months, sometimes she can just stroll into a shop and buy a book. Having just completed a several month stint as a scullery maid at a posh boarding school, Irene is looking forward to some down-time. Instead, she is told she is to mentor a trainee library agent and that they are to start their new mission immediately.
Irene's new assistant, Kai, is very handsome and very tight-lipped about his background. The Library never recruits anyone with living family, unless they are the children of other Library agents (like Irene) and therefore understand the need for secrecy and the strange customs and traditions that surround the work. He seems eager and helpful enough, but it becomes clear to Irene that he's not entirely truthful about where he came from, and she wonders if the senior librarians know of his falsehoods.
Irene and Kai are sent to a world resembling a Steampunk Victorian England. It is a world heavily influenced by chaos magic (some worlds are heavy in magic, some are almost devoid of it. Some worlds are highly technologically advanced, some very primitive) and there are vampires, werewolves, sinister dark fae and mechanically enhanced alligators waiting to attack. Irene and Kai discover that the owner of the book they're after was a vampire, recently murdered rather spectacularly. A cat burglar with a glamorous reputation appears to be involved and the fae ambassador for Lichtenstein is very keen to get his hands on the book, as well. To complicate matters further, Irene receives word that Alberich, a centuries old Librarian gone rogue and evil, is also in this reality, wanting the book for unspecified reasons. Their mission, which was supposed to be a fairly innocuous training exercise is turning out to be very dangerous, and they'll be lucky if they even survive, let alone succeed in getting the book back to the Library.
The world-building in this story is intriguing. There's the Library, where they clearly have fairly advanced technology, existing in a place where time apparently stays still. No one ages while within its walls. The agents of the Library can travel in both space and time, visiting hundreds of alternate worlds, some very like our own, some very different. The agents are trained in the use of magic, and there is a secret magical language that can be used to manipulate the world around you, but only if you speak it with the right vocabulary and inflection. Who exactly runs the Library and how one ascends through the ranks to become Librarians or even Senior Librarians was only hinted at, but I hope it's revealed in later books.
The main characters, Irene and Kai, were fun to spend time with. All agents take their names from literary characters and Irene loves all kinds of detective fiction, so named herself after the famous Ms. Adler. Being sent to a world that so closely resembles the setting of her beloved Conan Doyle novels is thrilling to her, especially when they befriend a gentleman detective who certainly fits right into the genre Irene so enjoys. Having always been aware of the Library, she doesn't really question its organisation, and how it goes about recruiting people. She starts having questions once she gets to know Kai more closely, though, and wonders if it's right that only people wholly unconnected in the world get to be recruited.
While there is a more contemporary, modern setting to some bits of the book, most of this is set in a Steampunk, late Victorian setting, with dirigibles and the occasional mechanically enhanced menace. There are quite a lot of action sequences, with our protagonists finding themselves in peril of various kinds. One of Irene's rival agents from the Library pops up with her own agenda, and there is the looming threat of the sinister Alberich. As a first book in a series, it was a good introduction. I certainly want to read more.
What I'm not going to do is continue with the audio books. The audio book (which I got in a big Audible sale last year) is narrated by Susan Duerden, whose inflection is just so annoying. Her voice had a tendency to go up and down at the strangest time, and she frequently ended sentences on a high point, making it seem as if everything was a question. It was incredibly distracting, and meant that I spent much longer getting through the audio book than usual, because I actively avoided it for a time, just because the narrator's voice was so grating to me. Searching the Audible catalogue, I notice that she's the narrator for the sequel of this, as well as for a lot of other books in fantasy and romance. I'm going to have to pay attention when getting new audio books, because I'm not interested in having this narrator worsening any more listening experiences for me.
Judging a book by its cover: I quite like the cover design, with the green, slightly marbled background and the almost golden font and decorations of a lady and a gentleman silhouetted in period costume. Not entirely sure what the snakes at the top have been included for (there are no snakes in the story as far as I can remember), but they add a sense of danger, I guess. The cover designer could possibly have made more of an effort to try to convey more of the adventure and action aspects of the book - if you remove the rather cheesy taglines, there's nothing to suggest to a reader that this isn't just some sort of run of the mill historical novel.