Yoko, a high school student, lives with her brother, Kenji. Since they lost their parents early, they have been supported each other. One night, Yoko witnesses Kenji, who is planning to get married, having an affair with Misa. Kenji’s cheating makes Yoko frustrated; however, Yoko felt uncomfortable and unsatisfied with Kenji's fiancé, Kaho, because Kaho suddenly cut into life of Kenji and Yoko. In a weekend, Yoko tails Misa and decides to speak to her. Compulsion and curiosity make Yoko confront Misa, but Yoko is seduced by Misa’s gentle and strong yet unstable character. Then, Yoko tells Misa, “Why don’t we stop my brother’s wedding?” A strange complicity relationship between two women begins.