On August 12, 2015, Hasegawa proposed to Ichiko. Ichiko is moved by Hasegawa's proposal and sheds tears, but the next day, she suddenly leaves home, seemingly shocked after seeing the TV news. Where did Ichiko go? Hasegawa reports the disappearance to the police, and the detective in charge of the investigation tells an unexpected story.

Three girls - Miwa, an introvert who's best friend is her turtle, Saori, a rich girl from a celebrity family, and Koyuzu, a member of a revenge agency - wind up in a complex rivalry with one another.