This is a fascinating book that takes place in Japan's past, at a time when there was a great deal of trouble in the country with warrior monks, feuding families, and, in this case, mythological creatures that turn out to be real.
Mitsuko is from a well-off family, but everything falls apart and she ends up going on a search for the spirit of her sister's dead husband in order to bring her sister's soul back to her. Mitsuko becomes involved with a shape-shifter, and the story just keeps getting more interesting.
Mitsuko is not perfect. She has a lot of prejudice against those who are not as wealthy as her family, and she tends to look down on the way that type of people live. She does manage to grow up a little in her attitudes become everything is over, fortunately.
It's a really good, very, very interesting book.