One day, Kuzumi Kentarou was assaulted by a gangster, leaving him heavily injured. While staying in the intensive care unit (ICU) of a hospital and being semi-unconscious, he saw the image of a beautiful girl saying his heart was "compatible" with hers. After he recovered from his injuries, he bumped into that very girl, Hasegawa Kirin, again.
It was then that he learned that she had innate hypertrophic cardiomyopathy (HCM), and his human leukocyte antigen (HLA) was completely compatible with hers, which was not only a miracle but it also meant that Kirin needed Kentarou's heart -- literally. Will Kentarou be able to give up his heart for hers, or will fate not be so kind to either of them?