If you haven’t yet read Soulless then I am afraid that this review will contain spoilers. It is the second book in a series after all. However, the spoilers are, in a way, not spoilers, because you pretty much knew what was going to happen simply becasue of the conventions of a romance. But nevertheless, consider your self warned.
Soulless ended with Alexia becoming Lady Maccoon after marrying Conall Maccon, as well as muhjah to Queen Victoria. Muhjah being the traditional preternatural advisor to the monarch, alongside a hiveless vampire and a packless werewolf. Changeless begins with her husband disappearing off to Scotland after his old pack. A strange lack of supernatural ability in London. And Alexia following Conall to Scotland on the trail of whatever caused the temporary supernatural-less-ness. And she travels on a dirigible. How very steampunk!