A Killing Frost

Just when Toby has finally adjusted to the idea of going through with her wedding to her dearly-loved King of Cats, a pair of selfish fae decide to put her into jeopardy as a way of getting what they want: Toby the investigator to find their bewitched missing lover and bring him back to them. What's more, a prophecy is issued by a seer that she will fail if she takes with her the support people on whom she would ordinarily depend for such a quest.

There are a couple of good twisty mysteries with satisfying resolutions in this one, along with some additional worldbuilding development.

The bonus novella, Shine in Pearl, tells the early history of the polyamorous relationship of three fae and how they almost broke apart before finally getting together. Whereas many of the bonus novellas which have been included with the October Daye novels are sequels and should not be read before the larger story which precedes them, this one is a prequel to A Killing Frost, and may actually enhance the novel for readers who have missed or forgotten parts of earlier installments.

But as with most of the later entries in this series, readers who haven't read the earlier novels will likely be lost both in the novel and the novella here.