Former teacher Shiho secretly gives erotic lessons to her former students while teaching calligraphy. She passionately instructs Haruo in sex, fulfills Takashi's desire by using a brush to stimulate his cock in a lewd act, and performs naked calligraphy for Shinji, surrendering to pleasure as she's caressed. Declaring it someone else's turn, she initiates a threesome. Using restraints, vibrators, and dildos, she indulges in relentless depravity, climaxing repeatedly in an unending series of pleasures.