Mary Tachibana's character is caught in the strained relationship between her husband and her father-in-law, causing her immense stress. To cope with her emotional pain, she secretly pleases herself through masturbation every night. One evening, her father-in-law sneaks into her room and witnesses her in the act, seeing everything up close. The shock and humiliation leave deep psychological scars. The situation worsens when she accidentally breaks an old ceramic piece cherished by her father-in-law, further deteriorating their already tense relationship. These events trigger a profound transformation in her life.