Sota, who married the daughter of the Ohara family as a son-in-law, spends his days fascinated by the plump breasts of his mother-in-law, Rio. One day, Sota decides to help Rio stretch. Sota, who has reached the limit of his patience with the huge breasts swaying obscenely in front of her, attacks Rio. Sota sees through Rio's timid personality and seeks out Rio even more. Their actions escalate, such as playing with Rio's naked body covered in bubbles in the bathroom, hiding in the middle of family reunion and being immersed in love affairs.
