Kasane; the most intelligent, beautiful, celebrated oiran in Yoshiwara; kept a "secret" which she could not share with anybody since the day she first accepted a client. This secret is kept in order to protect her memories with Tetsu, an unforgettable and treasured person to her. One day, a young samurai named Kei comes to her as a client. Kasane falls for Kei, who is both gentle and strong. However, at the same time, when she sees Tetsu's face when she looks at Kei, Kasane's faint love is stirred up immensely–