Seong Seowol, the eldest daughter of the Seong family, is obsessed with erotic art books and harbors intense fantasies about romantic intimacy. Having delayed marriage past her prime due to her father's fierce opposition, she suddenly finds herself wedded to Gyeongho, a young master rumored to be fierce and menacing in town. Contrary to Seowol's hopeful expectations, Gyeongho puts up an iron wall, and their first night together fails to happen... "There's no way my husband is impotent..!" Suspicious of her husband's lack of worldly knowledge, Seowol resolves to take matters into her own hands and tutor Gyeongho herself. On the night of the full moon every 15th of the month, a seductive and steamy intimacy class begins between the two.