Number six in the urban fantasy series featuring Mercy Thompson, Walker. And a walker, if I've got it right (and I should have, after reading all six of these stories!) is a Native American shape-shifter, presumably based on the Navajo legend of the "skinwalker"; but the skinwalker was evil through and through whereas the walkers in Patricia Briggs' books are either definitely among the good guys or at their worst amoral, as a cat (or any animal) is amoral. They are also very different from the werewolves, who, like the vampires, are of European descent – and like the vampires virtually immortal.
This is the first one in the series, though, where vampires get hardly a mention, and only one werewolf plays any significant part – Mercy's mate/husband, Adam, who is there (but actually rather in the way much of the time) because they are on their honeymoon.
Here it is all Native American medicine men/sorcerers, and shape-shifters who, like Mercy, are walkers and change shape easily and almost instantly, unlike the poor werewolves.
But she is still the only coyote. Apart, that is, from Coyote himself. For here we are presented with an original interpretation of Plato's Theory of Forms. Coyote (with a capital C) is the Form of which all coyotes are instances, just as Bear is the Form of which all bears are instances: godlike figures who, it is hinted, lay behind the animal-headed gods of antiquity both in America and in Egypt and India.
But I mustn't tell you too much. Simply that people, whole families, are dying or simply disappearing in or near the Columbia River, precisely where Mercy and Adam are honeymooning. The FBI think it is the work of an elusive serial-killer. Mercy soon realises that the killer is an ancient evil resurrected in the black depths of the swirling water . And only she, it transpires, can stop it ...