Nana is forced to move to the countryside due to her husband's job transfer. She feels increasingly anxious about leaving behind her brother-in-law, Tamotsu, with whom she currently lives. As moving preparations progress, her husband remains occupied with overtime work for the job handover. Emotionally disconnected and overwhelmed by loneliness, Nana impulsively kisses Tamotsu during a late-night drinking session. That single act transforms their relationship, deepening their bond in secret while her husband is away. An affair quietly weaves itself into their daily lives, unfolding with intimate intensity.