Haru wa Akebono Satsujin Jiken

This volume contains two short works by Yamato Waki-sensei.

Haru wa Akebono Satsujin Jiken (orig. published in 1991 but collected for the first time in this volume):
During the Heian era, Emperor Ichijo and his Empress Chuuguu Teishi's quiet romance faces trouble as rival political families seek to gain more influence in the court. When a couple of dead bodies are discovered and rumors of an oni abound, the palace's most intelligent female, Seishou Nagon, begins to investigate...

Lady Mitsuko:
This story was also published as its own tankoubon in 1977 , the summary of which can be found here: http://myanimelist.net/manga.php?id=17830