I am a big fan of the Shannara world by Terry Brooks. And Grainne Ohmsford is one of the most intriguing characters I've run into in this epic fantasy series. Tanequil continues the story of her involuntarily journey into the Forbidding, a land full of demons and other nasty evil things, and her nephew Penderrin's search for a way to bring her back.
Penderrin finds himself searching for a magical talisman that will allow him to enter the Forbidding, find his aunt, and bring her back. But as any reader of epic fantasy well knows, magical talismans come with a very high price. Terry Brooks does an excellent job of showing that payment isn't always a physical sacrifice, sometimes it's emotional as well. Penderrin's experiences as he obtains the Tanequil were some of my favorite of the book.
Meanwhile, Grainne finds out the same thing in a slightly different way. Not all punishment is physical, and she begins to lose herself to the magic of the Forbidding. Enemies and allies in unexpected places really brought this realm to life. It truly is another world within Shannara, and I can see why the elves first sealed it away. I can't wait to find out if she will be the same person or something completely different by the end of the series.