Yuko, a married woman whose husband is a banker, deeply loves her cheerful and energetic husband. But lately, she's sensed a coldness in his behavior, leaving her with quiet unease. One day, her husband's coworker, Fujihara, suddenly visits their home, stirring emotions within Yuko. To help her husband, a bet unfolds between Fujihara and herself. As a result, she's forced to confront her own true feelings, bringing unexpected change to her relationship with her husband.