Misaki has been attending a women's university in Tokyo since this spring, and has been living with her boyfriend, Kenji, who is her senior in high school. However, one night she discoveres that he cheated on her and leaves him. She has no money and no place to go Misaki is in the women's dormitory at the university. She decided to enter the "Shirayuri Dormitory". The people who gently called out to Misaki were Shizuka, a fourth-year student and dormitory director, and Saori, a third-year student. A welcome party was held in Shizuka's room, and when Misaki returned to the room, Shizuka and her friends were in a mysterious atmosphere. The two were lesbians. Shizuka then taught Misaki about her university life, and she said that she thought of herself as her real sister and that she could talk to her about anything.