Rika and Atsushi are a close-knit brother and sister. They have been inseparable since childhood, known in the neighborhood as an incestuous pair. Although they each had boyfriends and girlfriends, none of those relationships lasted long, seemingly because they found being together more comfortable. Rika, wanting to make her beloved brother happy, started researching AV material. She first learned about cuckold play. She earnestly attempts cuckold play but ends up getting the upper hand by her sadistic yet kind older brother.
