Hall keeps the tone of Sir Arthur Conan Doyle's stories by framing The Affair of the Mysterious Letter as if it was a printing of a serial article previously published in a newspaper, with some slight editing between the original publications and the compendium presented to the reader. This means that the Watson-esque character, Captain John Wyndham, is recapping his adventure to the reader and telling the story as reliably as he chooses. Wyndham claims he doesn't change anything of significance and he often notes when he edits the events. Most of these alterations to the actual events come in the form of editing vulgar statements or refusing to convey certain events in any real detail because Wyndham's own sensibilities and upbringing in a very conservative household and country are often at odds with some of the experiences the Sorceress Shaharazad Haas (this story's Holmes-analogue) put the narrator through.
Much like the first Sherlock Holmes story, A Study in Scarlet, The Affair of the Mysterious Letter begins with Wyndham leaving his military service and looking for a place to stay. In the case of this story, he eventually ends up lodging with the well known sorceress, but quickly realizes that the two have very different views on both what is moral and what is fun. In this sense, Hall takes Holmes' more frowned upon habits to extremes, and adds a few more vices for good measure. The pairing of these two characters ends up causing quite a few Odd Couple moments as they play off of each others' expectations.
As for the book's mystery; it focuses on one of Ms. Haas' former lovers, Ms. Eirene Viola, who is now engaged and soon to marry a rising star in a local merchant guild. Eirene storms into Haas' flat at 221b Martyrs Walk suspecting Haas of blackmailing the bride-to-be in order to force Eirene to call off the wedding. This kicks off a series of events that have Haas, with Wyndham in tow, investigating possible blackmailers in underwater cities, worlds in different realities, areas that take place in a different time, and all manner of other unusual settings. Along the way, the pair will have to contend with everything from necromancers and vampires, to witches and beings that exist in multiple times and realities concurrently, and even a landlady that is a sentient hive of wasps that animates a corpse. That last one would be their own landlady, the Mrs. Hudson-like character.
Early on, Haas proves herself to be very Holmesian in that she is quick to deduce many facts from short observations, but she also has a lot of power at her disposal as she is an apt sorceress, something that gets the pair both in, and out of, a lot of trouble. During many points in the book, I found myself worried that whatever final events revealed who the blackmailer was, it would be Haas' magic that resolved the mystery. A big part of Holmes' appeal is that, for the most part, his wits are his primary tool. Suffice it to say my worries were unfounded and while Haas' powers did add a lot of flavor to this story's decidedly fantasy setting, most of the detecting relied on the character's deductive reasoning.
Hall's setting for The Affair of the Mysterious Letter is a strange one that only resembles our world in passing. Countries and political structures are nothing like ours and Wyndham often makes excuses in his telling of the story to describe what he readily admits most people should know, but this does make for an effective way to describe to the reader the strange place the story is set. Unfortunately, I found the fact that the world is so different from ours somewhat off putting at first. It's clear that Hall had a strong image of the world in mind when writing this book and wanted to convey as much as possible to the reader, but it made for a very daunting first portion of the book. Once the mystery got rolling, it was far less of a drudge, but it did take some effort to really get into the swing of things.
The only other part of the story that I feel is worth mentioning to potential readers is the nature of relationships in The Affair of the Mysterious Letter. With the exception of one pair of minor characters, I don't believe there was a single relationship one would call normal or "cis." Every major and secondary character exhibited some form of homo or bi-sexual tendencies and the book was very in-your-face about these relationships. It was so prominent that it sometimes felt a little forced and it almost felt like the book was trying to be so inclusive that it alienated me as a reader at times. Suffice it to say, if a book involving these types of relationships offends you, then I don't think any desire to see a Sherlock Holmes tale in a heavily fantasy-driven world will make up for this book's portrayal of relationships. Even if you are very middle-of-the-aisle when it comes to sexual preferences, you could still find the very slanted view this book presents as a bit overpowering.
In the end, these criticisms didn't hurt my overall opinion of The Affair of the Mysterious Letter. While the writing is very flowery and the narrator is sometimes a bit overly verbose, I feel like it was necessary to catch the tone and feel of a Sherlock Holmes story. At first, I wasn't sure if I would be interested in the further adventures of the Sorceress Shaharazad Haas and Captain John Wyndham, but at this point, I am intrigued to see what Alexis Hall has in store for the pair's next adventure.
