Sophie lives in an alternate Scotland around 1935, in a world where Napoleon won at Waterloo, and Scotland and the Scandinavian countries have established a new Hanseatic League to resist being forcibly joined to the rest of Europe. Terrorist bombings are increasing, and the Scottish minister of public safety is calling for war. Spiritualism is very real, and consultations with the dead through mediums are common.
In these turbulent times, Sophie wants nothing more than to go to university and study science after leaving her girls' boarding school. Instead, she fears she'll be forced to join IRYLNS, a governmental agency which trains young women as personal assistants to male government officials, and perhaps does more than simply train them, as Sophie finds out when she visits with her aunt. And when a medium at her aunt's house delivers a frightening prophecy to her and then is murdered, Sophie and her friend Mikael must unpick a tangled web of lies, violence, and political intrigue.
I liked Davidson's taking-off point for her alternate history and the idea of the New Hanseatic League, and I thought she created a believable political world. She's rather too prone to drop famous names into the narrative, arbitrarily changing their professions and lives -- for example, there's a reference to "the theology of Count Tolstoy, the novels of Richard Wagner, the verse of Albert Einstein, or the operas of James Joyce" -- which I found distracting at first and then just annoying. I can see how this might be hard to resist, but I would much rather have read more about how the political history of the world had developed.
I quite liked clever, scientifically-minded Sophie herself, and I liked her complex relationship with her aunt (and how her aunt, who feels that emotion is bad, tries to deal with her love for Sophie) and with her friends at school. The understated romance is handled nicely, and also Sophie's schoolgirl crush on her chemistry teacher, with its attendant awkwardness and misery.
Davidson does a good job in adding detail and complexity to the plot slowly, so that Sophie's race to solve the mysteries becomes more and more tense. I wish I had known in advance that a sequel is in the works, as I found the ending overly abrupt. Still, I'll definitely be reading the sequel.