The oldest daughter of the Asahina clan, Asahina Tsubasa, who is Asahina Masaomi's twin-older-sister, stayed in America for five years to stay in the hospital. She has a rare kind of asthma that can cause her to die. Actually, nobody in the Asahina clan doesn't know about this except Miwa and Rintarou. After 5 years, will her brothers recognize her again? What will happen if she meets Ema?