Japan's number one bestselling high teen novel!! A charming series of events unfolds at a ladies' school with the new members of the Sanbaiyukai! Asakura Momo suffers from unexplained dizziness ahead of her mother's remarriage. One day, after collapsing at school, she is escorted home by Tsutsui Tamaki, the health committee member. From then on, Momo feels both burdened and gradually opens her heart to Tamaki, who approaches her closely. However, a sudden suspicion arises in her mind—could Tamaki be a relative of her mother's fiancé? Momo, a first-year student, and Tamaki, a second-year student. Their classmates start to imagine that the two of them, who are often together, might be sisters!