Sayuri, a mother who can't hide her loneliness after the death of her sickly husband, is cheered up by her only son, Daisuke, who offers to be her surrogate husband. The two of them live together earnestly and happily, and Sayuri gradually regains her smile. However, her son begins to develop romantic feelings for her... He sneaks into Sayuri's bedroom and, unable to control his lust, rapes her.