Emi enters into an inappropriate relationship with Mizuki, the student council president. Despite Emi telling Mizuki that they will only have sex once, Mizuki’s sexual desire knows no bounds. This desire is released at school, in the hallway, in the school storage room, anytime, anywhere, leading to her having sex without them realizing it. In addition, an important hidden secret comes to light, leading to a drastic change in the relationship between Emi and Mizuki.