Since moving in with his mother-in-law, Mariai, Kazuya has been unconsciously captivated by the allure Mariai exudes. Despite knowing she is someone he shouldn't think of inappropriately, his desires refuse to go away. During such times, he caught a glimpse of Mariai changing clothes. Her breasts, about to spill out from her corrective undergarments, and her tightly bound, plump buttocks... Kazuya is ignited by Mariai's fully matured, voluptuous body.