Yumi, who raised her son Kousuke all on her own, begins to develop romantic feelings toward him as he comes of age. Torn by confusion and inner conflict over these emotions, she suffers deeply. At that moment, her husband—whom she divorced twelve years ago—returns, demanding reconciliation and presenting evidence from a hospital proving Kousuke was switched at birth with another child. Upon learning the truth, Kousuke falls into profound despair, fearing the destruction of their bond. Yet Yumi gently embraces him, radiating warmth and strength amid the chaos, giving rise to a new and intense drama.