Silver Borne by Patricia Briggs

When Mercy Thompson, mechanic and shapeshifter, attempts to return a powerful fae book she previously borrowed in an act od desperation, she finds the bookshop locked up and closed down. It seems the book contains secrets - and the fae will do just about anything to keep it out of the wrong hands. And, if that doesn't take enough of Mercy's attention, her friend Samuel is struggling with his wolf side - leaving Mercy to cover for him lest his own father declare Samuel's life forfeit. All in all, Mercy has had better days, and if she isn't careful she may not have many more…"

I love how Adam and Mercy's relationship us growing. Some of the characters from previous books make an appearance. Lots of action and interest. Another great book in the series.