Yayoi, a mother, is fed up with her husband who has been cheating on her since they got married, even when he is not at home on holidays, and pours all her love into her son Kota. Kota grew up watching his mother's lonely back and before he knew it, he thought, "I'll take the place of that terrible father!" Then, Yayoi's feminine heart was stirred by her son's reassuring words, "I'll protect you, Mom."