Yuya and Sumi live a quiet life together in Tokyo. Living with them as a lodger is Mitsuha, Sumi's younger sister and a vocational school student. Mitsuha is a gentle, somewhat vulnerable beauty who catches the eye of a certain man who begins treating her as his girlfriend. This man, Hinata, belongs to a semi-delinquent group, and together with his gang members, he harbors malicious intentions not only toward Mitsuha but also toward Sumi. Before long, repeated brutal NTR encounters take place right in front of Yuya, subjecting both Mitsuha and Sumi to nine months of extreme humiliation. As a result, their bodies eventually carry something far beyond what anyone anticipated.