The novel follows the diary entries of Ikuko and her husband and their deteriorating marriage. The husband grows dissatisfied with their sex life and hatches a plan to manipulate Ikuko into becoming more sexually adventurous by getting her drunk on brandy every night. This leads to several incidents where Ikuko loses consciousness and the husband takes intimate photos and touches her without consent while pretending to be her lover Kimura. Their daughter Toshiko disapproves of the husband's treatment of Ikuko. The novel explores themes of sexuality, fetishism, and the breakdown of trust in the marriage.