Hina Fujisaki is a 38-year-old housewife who met her husband in school and married him, enjoying a comfortable and familiar married life. While she shares a close bond with her husband and enjoys each day, she has recently begun questioning her self-worth as her husband advances in his career and her son grows older. One day, her son comments that her husband's late returns home must mean he's cheating, sparking deep anxiety in Hina. That's when she ends up crossing the line with her son.