Kana has been engaged in a long-term affair with a married man, Sakurai, who has a wife and child, for 15 years. However, one day she suddenly meets a sincere and kind man, Yoshimura. This encounter begins to drastically change Kana's life. Torn by her feelings for Yoshimura, she eventually resolves to end her relationship with Sakurai. Kana arranges to meet Sakurai in person to break things off. From that day onward, her happiness with Yoshimura rapidly begins to collapse.