Yuka's love of reading led her to become interested in literature, and she aimed to become a researcher at a national literature department. However, she is now married to her husband whom she met while she was a student, and lives an ordinary life as a full-time housewife. With her only son growing up steadily and being a handful, Yuka has too much free time on her hands. One day, her son brings his friends over for a sleepover study session. Yuka is to participate in the study session as the teacher, but as she stares into the innocent Hitomi of her son's friend, Yuka's abnormal sadistic tendencies are awakened...