Three years after their marriage, Nao and Yusuke were happily living in a low-rise apartment. One day, Nao is invited to a party by Watanabe, who lives on a higher floor. Yusuke is reluctant to go, but Nao, who has some aspirations for a wealthy life, secretly joins the party on a day when Yusuke is coming home late... They share the same apartment, but in a “high-class” room with a completely different view and size, and over drinks, Nao allows herself to be seduced by Watanabe, and even has s...