After divorcing, Midori gave up custody to her husband and began living apart from her son, Hiroaki. Separated from Hiroaki, Midori was overwhelmed with sorrow and regret. As loneliness and anguish grew inside her, she entered into a forbidden relationship with Hiroaki. Several years have passed since then, and Midori is now permitted by her ex-husband to meet Hiroaki only once a year. Recently, she learned that her former husband has remarried and that Hiroaki now has a new mother. This news stirs within Midori complex emotions toward the new stepmother who has joined her son's life.