Tsubaki felt burdened when she was left alone with her father-in-law during her husband's business trip. This was because her father-in-law had romantic feelings for Tsubaki. During her son's absence, her father-in-law finally had a relationship with Tsubaki. Her father-in-law's vigorous stamina and skilled sexual techniques awakened the 'sexual desire' within Tsubaki. Tsubaki began to seek out her father-in-law as a 'woman'.
