Arthur A. Levine Books (Scholastic), 2010
Let me start at the end: I was reduced to not a slightly teary, not a delicately weepy, but a blubbering, sobbing mess at the end of this book. I haven't cried so much because of a book since I struggled to read the last chapters of Tolkien's The Return of the King through a veil of tears, a comparison which may give you an indication of both how invested I was in the characters and the effectiveness of Bow's world-building.
Bow's prose certainly reflects the fact that she is a published poet, with phrases like "the sky had slid shut under a lid of low clouds" (p. 30) appearing throughout. This lyricism lent itself well to the dark, magical world that Plain Kate inhabits and tries her best to make her way safely through. The book is very atmospheric, and I could almost feel the cold damp of the fog traveling upriver, or hear the mud pulling at the bottom of Plain Kate's boots. The novel has a distinct Medieval, Eastern European feel to it, with towns and cities located at great distances from one another and tinkers and merchants selling their wares in outdoor markets.
Plain Kate is an evocative main character. She reveals herself slowly to other characters as well as to the reader, and coming to know her gradually made her feel all the more real. Her constant companion, Taggle the cat, is a wonderful comic foil to Plain Kate's seriousness while remaining an exceedingly loyal companion (despite his derision for dogs). Secondary characters, such as Drina and Behjet, are three-dimensional with their own tangled beliefs and personal sorrows that are hinted at and not always explained, leaving the reader to draw their own conclusions. As in reality, people and events were not always tied up neatly, which makes it easier to believe that the world in Plain Kate has no boundaries and continues to exist.
Although it took me a few dozen pages to get truly sucked into Plain Kate, once I was in it I wasn't prepared to leave until I got to the end. Had someone asked me after the first chapter if I would be an emotional wreck at the end of the book, I would have given a definitive no. I am exceedingly glad that I would have been wrong, and I will be recommending this book to many.
Edited February 15th to add: I just found a fantastic book trailer for Plain Kate made by Scholastic: