On a weekend, in a Tokyo residence, a hardworking salaryman living with his wife is frantically cleaning the house in preparation for his mother-in-law's arrival. Anticipating the visit of his wife's mother, who has traveled all the way from the countryside by train, he braces himself mentally. When the doorbell rings, in steps his mother-in-law, Manami Ishino. Overwhelmed by her seductive presence, he can no longer suppress the rising emotions deep within his chest. In that instant, his heart is profoundly shaken.