Jeaniene Frost's Night Huntress series was recommended by the SBTB, despite their disliking of series books. It looks like Frost's intention with the Night Huntress World spinoff is to create single-entry romances for side characters from the Night Huntress world. This first outing stars Spade, Bones' fellow convict from New South Wales (formerly courtesy-title Baron whatsis, son of Earl of somesuch, who racked up a lot of debt and enemies, hence, his son winding up transported), and Denise, human best friend of Cat, the Night Huntress. The end matter on this entry includes a note from the author describing who will be in the next entry in this series (Mencheres, Spade's sire, and a newly created character, Kira). Frost apparently is also continuing the Night Huntress series.
Could you read this as a standalone book? Maybe. There would be comments that would make no sense at all (who's Rodney?), but meh. It should mostly work. This novel supplies backstory for characters present in the main series, which is potentially interesting to followers of the Night Huntress series. Is it necessary to read this to follow events in the main series? Meh. We won't _really_ know until the next entry comes out, but nothing that happened in this book seemed likely to introduce a discontinuity in the other series and very little new was introduced in terms of powers and so forth of the main characters.
What happens? Denise goes drinking with a cousin, who is killed by a shapeshifting demon in the parking lot that night -- after Denise tries to mace and then silver-nitrate-spray the demon, with no particular effect that she can see. The demon thinks this whole silver thing is interesting, and comes after her with an offer she can't refuse: find your ancestor (I figure he must mean collateral relative up the tree, because there's no indication Nathaniel reproduced) who made a deal with me and then left without paying up his soul, or I keep killing your relatives. After attempting to call the few supernaturals she knows well (Cat, Bones) but has cut ties with since the New Years Eve of Teh Awful that killed her husband Randy and gave her the never-get-over-PTSD-flashbacks-whenever-a
They both have motives for keeping Cat and Bones out of it (also relevant, the author is highly motivated to keep Cat and Bones out of it), but figure Nathaniel must be hanging around vamps or he would be dead by now. It turns out Nathaniel _is_ hanging around vamps, but he wouldn't be dead either way; everyone has been seriously underestimating the effects of the demon marks er, brands, that Denise now has as Nathaniel has, and will continue to do so (mysteriously so, in fact) for the rest of the story. Denise and Spade gradually come to accept their attraction for each other as they meander about the globe visiting gambling hot spots in search of the dealer of Red Dragon, vampire happy juice. Which it turns out is another effect of the demon brands.
The backstory about Griselda helps, marginally, the reader accept Denise's perpetual craziness -- apparently Spade picks women like this. They run when they should stay put. They think they can take care of themselves when any dumbass could see they were way out of their depth. They both strenuously resist Spade's efforts to turn them into a vampire in an effort to make them slightly more death resistant. Denise's survival is no thanks to her -- really, it was the demon Raum making her so damn unkillable and then sending her after the one guy who could explain to her how to kill Raum. D'oh. That demon is too stupid to live. It makes a lot of sense that Spade would pick women who don't want to become vampires and have a stupid desire to sacrifice for others: that's basically exactly the kind of person his backstory says he is.
The story moves along at a good clip. The characters are at least somewhat appealing (altho definitely IQ challenged and not _nearly_ inquisitive enough). The depiction of the sexual attraction is adequate.
If this were the first book in a series, I'd mark it down as, well, I guess I'll read more of it, if I've got nothing more compelling to read. Given that a new Kresley Cole novel is also sitting on my kindle, and I started it first, abandoned it, and read this one all the way through in under 24 hours, I will almost certainly continue to buy everything Jeaniene Frost puts out.
I guess if this is the kind of thing you like, you'll like this. Oh, and I did kinda like that the form Denise keeps almost shifting into, and then uses to kill Raum, is the nightmare that has been haunting her since that fateful New Year's Eve. Really Jungian.