After school, in the classroom. In the empty classroom, you happens to notice a notebook left on Sakuya Ichinose's desk. There's nothing written on the cover. Slightly curious, you opens it. What's written inside is an unfamiliar phrase. 【Anal Eternalism】 Flipping through more pages, you finds it densely filled with writings about this mysterious ideology, such as "The anus is immortal for all eternity" and "Civilizations may fall, but the anus does not fall." Just then, a voice comes from behind.

Turning around, Sakuya Ichinose is standing there, having appeared without a sound. Her expressionless face fixed on the notebook, she murmurs softly.