College student Yotsugi Megumi meets abandoned Furuhashi Kotoha near a garbage dump and brings her back home. Before they can become friends, Kotoha proposes a strange bet: the two will act as lovers until Megumi can guess Kotoha's real name. With the challenge accepted, a sad and strange tale begins...
Megumi and Kotoha spend a night together by chance, but afterwards Megumi accidentally sees Kotoha arguing with another man.
Kotoha's active approach starts working on Megumi, while Megumi continues to think about the challenge Kotoha has given her.
Megumi and Kotoha go out on a date. However, Megumi acts in an unexpected way at the end of their date.
Megumi tells Kotoha about her past; Megumi finds the man who knows Kotoha and asks him about their relationship.
Megumi and Kotoha spend a night together at a hotel, and through Kotoha's guidance the two of them become more intimate.
Kotoha’s past resurfaces as she clashes with a mysterious woman. Megumi tries to get close to Kotoha, but gets rejected.
After Megumi breaks up with Kotoha, she feels remorse for running away. She decides to search out Kotoha’s past, and discovers her real name and a story full of trauma.
Kotoha tries to draw a boundary with Megumi to bring their relationship back to friends. However, Megumi refuses to give up and goes all out for her love.
