Miwa Kanzaki is married to Hiroki Kanzaki and is a full-time housewife. She used to work for a large company, but made the difficult decision to quit her job and become a full-time housewife in hopes of having a child. But her marriage life isn't going very well as her love for her husband has cooled considerably. Hiroki acts like an ideal husband when around others, but he speaks harsh words to her when they are alone. She lives her days like a bird in a cage. One day Miwa meets her childhood friend Ryo Fuyutsuki, whom she hasn't seen in years. Back then, Ryo was like a hero to her and loved by her. When she was in trouble, he always came and helped her. They make the fateful decision to spend the night together and Miwa later finds out that she is pregnant with his child. She doesn't want to divorce her husband and become a single mom, because she doesn't have a job. To protect her baby, she decides to tell her husband that she is pregnant with his child.