A cheerful 18-year-old named Ichiko Izumiya lives in modern Tokyo with her father, a translator of English novels. While working at a music store and attending language school, she is in a loving relationship with her girlfriend, Eri Joujima, a beautiful and serious law student. When Ichiko musters the courage to come out as a lesbian to her father, she is met not with shock or rejection, but with an astonishing secret of his own. He calmly reveals that both he and Ichiko’s late mother were also gay, having entered into a marriage of convenience specifically to raise a child together while each pursued separate romantic relationships outside the home.

Reeling from this revelation, Ichiko is introduced to her father’s male partner and learns more about her mother’s female lover, reframing her understanding of her entire family history. The story follows Ichiko as she navigates the everyday joys and complexities of her relationship with Eri, who struggles to balance romance with the pressures of her academic ambitions. This leads to a trial separation, forcing Ichiko to confront her own insecurities and define her identity on her own terms. The narrative explores themes of acceptance and chosen family, showing a young woman discovering that her life and love are part of a larger, affirming continuum.