This is book 6 in the Mercy Thompson series, one of the few urban fantasy series I've been able to tolerate past the first book, mostly because of our protagonist. It would be fair to say, over the past few books, Mercy and her friends have been through the wringer a few times and River Marked is no different.
In this book, Mercy and Adam get married and go on their honeymoon, but of course (being an urban fantasy novel) they have to get involved in the goings-on of the area where they end up, though we discover quite early on that this isn't particularly an accident. While making arrangements for their honeymoon, Adam had pretty much agreed they would look into a series of disappearances which, of course, turn out to be because something supernatural is living in the river and eating people.
Alongside this, Mercy ends up exploring her own heritage in terms of her father and just who he actually was, which was something that had always been left hanging in previous books so I'm not surprised that the author decided it was time to address this more.
This felt very much like a bridging book, one that dealt with at least one thing that clearly needed dealing with, but one that left me ultimately a little unsatisfied. Not that this is going to stop me reading the next book (Frost Burned) or anything else in this series that the author might write!