Fifteen years ago, the Kouda sisters watched their father abandon them to begin a life with his mistress. Shortly thereafter, their mother deserted them, leaving their maternal grandmother in Kamakura to raise the girls. Now a working adult, Yoshino Kouda receives a phone call from her older sister, Sachi, bearing news that their father has died of cancer. Although Yoshino is not devastated by the news, she—along with her younger sister Chika—feels obliged to attend the funeral, as Sachi is unable to do so due to her work schedule. At the ceremony, the two meet Suzu Asano, their 13-year-old half-sister. After Suzu’s mother died, their father remarried. Suzu became the one to shoulder every responsibility, including caring for her father’s deteriorating health. Despite Suzu being a living reminder of their father’s infidelity, Yoshino and Chika cannot help but feel sorry for her. Surprisingly, Sachi arrives at the burial as well, witnessing the struggles Suzu has endured. A newfound sympathy leads Sachi to decide to bring Suzu into their immediate family. The four women must now learn how to navigate life and come together as sisters.