Sakuya's younger sister, Suseri, shows up. She also works to rid the world of monsters, and is a rival to the head of the Shimazu family. She wants to bring Shinichirou over to her side, so she attempts to seduce him, and eventually kidnap him, but they run into a bit of trouble with monsters on the way...

Shinichirou tries to cheer Sakuya up after he finds out that she might lose her right to become next head of the family. The secret behind Sakuya's birth, and why she's so hung up on taking over the family becomes evident. But then a monster shows up which will test her allegiances to the past, to the present, and to herself.

Sakuya is in a coma now that she's lost her spiritual energy, and Shinichirou would like nothing more to save her. Suseri decides to undergo the exorcism ritual after seeing Sakuya in her state. She must subdue a lightning beast on her own in order to make it into a shikigami, and during the fighting we learn about Suseri's hidden past and her feelings towards Sakuya.