Private Jibitatsu Gakuen … A famous school to gather talented students in every direction.
A large proportion of female students look gorgeous, but they have had many problems behind the scenes.
One of them is a self-governing group that manages the school called “Gakuseikai”.

Shinichiro Nissei, who attends such a school, lost her parents at an early age, but has lived happily with Saki, who is an elder sister and a teacher.
However, Saki is deceived by the people of the Gakushinkai, and falls into a loss of mind.

There was a person who called out to Yuichiro, who lamented without being able to save her love Saki.
Hiroko Shiraishi, a public health doctor who calls himself a “dark security officer of public safety”.
She asked Shinichiro to be a companion if he wanted to finish the school meeting.
Shinichiro, who regretted his powerlessness, whispers to the dark child.