I was invited by the author to review this novella and received an electronic preprint version for the review.
Carriger returns to writing for an audience of adults in the decade or so before Soulless.  For those familiar with her other works, this feels much closer to the Alexia novels than her more recent teen pieces and it’s a comfortable but intriguing return to a well known place.
There are spoilers in this review, if you would not like to be spoiled, please come back another day
In this transition between time periods of her other works, Carriger draws forward a character from the Finishing School novels, Preshea, who is now a fully trained and highly capable assasain. Sent on assignment to a house party in the North, Preshea encounters a Scottish Captain who might get in the way of her assignment and might mean more to her than a target or an irritant.
My first impression of Preshea was that I could see her getting along with Conall, the werewolf from the Soulless books, although undoubtedly he would take issue with her being female. She is presented as chilly and exacting, the type slightly feared at parties by women who mistrust her and men who are easily impressed by her beauty and thrilled at the idea of being around someone dangerous.
Carriger makes an unusual choice in having a more “broken” female character rather than the traditional cold and aloof male characters common in most romances. It’s well done and I appreciated the change in choice. Preshea is aware of her effect on people and has chosen to cultivate it, recognizing that it makes her lonely but uninterested in currying favor.
While the story is intended to be a stand alone, Carriger  — probably rightly– assumes familiarity with her universe. She does not waste time explaining how vampires and werewolves interact, vampire tethers, ghost naming conventions, etc. This will not be an issue for familiar readers but might cause some confusion for someone coming new to the series.
Plot spoilers really start here
Preshea’s assignment is unusually not to serve as an assasin but instead as a romantic disrupter for one couple and, under cover of that, as a bodyguard for another character. Gavin is in a similar bodyguarding position, albeit from a differnet quarter, and along as the friend of a lovelorn jackanapes. One feature that was disappointing  was the abandonment of the attempts on the guarded character’s life after one rather paltry attempt halfway through the book. I kept waiting for a second attempt and it was brushed off as “into the future” which I saw as a missed opportunity for more romantic interplay.
The sexual tension between the leads was nicely done and the sex scenes had an interesting take to them. I tend to read an author’s first round of sex scenes and then skim through the rest, most authors writing more traditional romance don’t tend to put any big revelation of secrets in scenes readers might skim.
There are two interesting side plots– the lovers that Gavin is there to support and Preshea to break up and another pair of young ladies who have their own special connection. The search for scandal as the first pair finally realize they are not the best matched seemed unnecessary– wouldn’t young girls at a house party be up late giggling in each others’ rooms?
A few other familiar characters pop up. Everyone’s favorite vampire returns and I find I must have missed something, being two or three books behind in the Finishing School, as I don’t remember anyone talking about the apprenticeship work mentioned here. Carriger repeats one of the verbal ticks Akeldama has from Soulless in is enteractions with Alexia –not using names– but it feels strained in his conversations with Preshea and, had I not already known Akeldama’s habits and behaviors as head of a spy network, it would have seemed odd and would likely have ruined later books for me. I loved his ridiculousness in Soulless and that is missing here.
Overall it was a nice short trip back to Carriger’s world and I recommend it for Alexia fans. If you are introducing new readers to her work, I would continue to suggest Soulless  as the gateway, however, for best world building.