Kouichi feels the routines of his five-year marriage to Kanako and their young daughter settling into quiet monotony. When neighbor Kimihiko approaches him with an unexpected proposal to exchange partners in secret, the suggestion leaves him unsettled. As he considers the possibility of discreetly pursuing another woman, the idea of hidden meetings begins to awaken long-dormant curiosity. Still hesitant, he weighs the temptation against the stability he has always known.
