Mercy Thompson is one of the few urban fantasy heroines who isn't all lily-white -- she's half Amerindian, from whence her coyote shapechanging comes. 
 And Patricia Briggs' sixth urban fantasy "River Marked" delves into that oft-neglected side of her heroine. The plot is patchy and rather meandering at times, but Briggs keeps it moving with her strong earthy prose, likable characters, and some new insights into the world of shapeshifters. It's nice to get away from the Tri-Cities area! 
 When her mother starts overplanning her wedding to Adam (doves! Balloons! BUTTERFLIES!), Mercy decides to have a small, intimate ceremony instead. And they immediately embark on an idyllic honeymoon in a remote canyon on the Columbia River. But Mercy soon stumbles across some connections to her long-dead father -- other Amerindian shapechangers, ghosts, and true dreams. 
 As she searches for connections to others of her kind, Mercy stumbles across something much nastier, when she is "river marked" while rescuing a wounded man (who was bitten by something barracudaesque). The secret to dealing with the river creature will send Mercy back through ancient lore -- and the discovery of her father's true identity... 
 The previous five Mercy Thompson books all took place in the same general area, so it's a little refreshing to get out of town in "River Marked." Oh, the regular supporting cast makes appearances -- from the mopey Stefan to Mercy's cutthroat mama -- but most of the action takes place in the rugged canyons and murky rivers. 
 The biggest problem is that that the plot is pretty patchy. The main focus is on Mercy's search for her roots, so the river-monster and otterkin subplots sometimes get shoved to the sidelines. But Briggs' prose is strong and earthy, with some warmly snarky moments ("You stop baiting him -- or I'll call my mom") and some otherworldly ones (Mercy's talks with Coyote). 
 And it's good to see more exploration of Mercy's roots -- we know she was raised by werewolves, but Briggs really delves into her mystical, mysterious heritage here, and it adds a new dimension to her without seeming Mary-Suesque. Almost as important: she and Adam are now a full-fledged couple in every sense of the word, but they still have some wrinkles to iron out. 
 Patricia Briggs' "River Marked" is light on plot, but heavy on atmosphere, characterization, and a suitably monstrous magical foe. It's not the best of the series, but it's a powerful book.