Iron Kissed

This is the 3rd installment in the Mercy Thompson series by Patricia Briggs, a series I discovered via the "New Releases" display at the library with Frost Burned. I immediately set out to read then in chronological order (see also Moon Called and Blood Bound) and I am well and truly hooked.  These books are so compelling that I really struggle to put them down and go to sleep! That hotbed of supernatural activity, the Tri-Cities in Washington state, is the setting for these books, and Mercy is a Native American shapeshifter--becoming a coyote at will--and also a "Walker." This gives her powers, e.g., to communicate with ghosts and detect magic, which even the other supernaturals in the area do not have. In this book, Mercy is called upon by mentor Zee to assist with solving a series of murders. Zee trained her as a car mechanic and then sold her his car repair business. He is one of the rare fae (fairies) who can handle iron, i.e., "iron kissed,"  and is hundreds of years old, although he doesn't look a day over 75. Mercy's extraordinary sense of smell when in coyote form means she might be able to detect who was at all the scenes of murder on the fae reservation, so she agrees to help.
The higher ups of the fae world, known as the Gray Lords, will do almost anything to keep non-fae from knowing about the extent of their magic, and are even willing to let Zee die as a scapegoat to keep public attention from themselves.  Mercy puts herself at real risk by going onto the reservation, where she encounters magical artifacts, other worlds, and very powerful fairies, who would just as soon eat her or kill her as look at her. She is not willing to let Zee die for something he did not do, however.
Mercy's other big problem in this book is making a decision about Sam vs. Adam, two dominant werewolves who both want to lay claim to Mercy as a mate, and both of whom Mercy loves in her own ways. Nevertheless, Adam's pack comes out in force to support Mercy when she is attacked by a voracious monster fairy. However, in the end, it is humans mis-using stolen fae artifacts who present the real danger to Mercy; although she makes it out of this encounter phyically alive, she is psychologically brutalized and struggles to regain her sense of self and safety in the world.