Shinichirou has the Eye of Truth and it allows him to figure out people's true names, but Sakuya doesn't want anyone to know her true name, so she's keeping Shinichirou away from her.

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.

I will defeat you with my own hands, Sakuya Shimazu!