A review by coffeeandink
The Story of Saiunkoku, Vol. 1 by Sai Yukino, Kairi Yura

VOLUME 15
Title: 暗き黄昏の宮 (Kuraki Tasogare no Miya)
Anime: Post-anime (Shuurei falls into a coma and Ou Ki's plan is revealed)
Published: December 2009
Summary:
Scans from volume 15 by
Charmian reports spoilers from Japanese blogs
Translation:
http://saiun.wordpress.com/2010/01/saiunkoku-novel-15-table-of-contents/