A young man's (played by Eita) sister was killed by his close friend some 15 years ago. He made a promise to his mother that he would take care of sister, but that promise was broken. Because of the death his family separated. The man has lived with guilt of his sister's death ever since. One day, the young man meets a woman (Hikari Mitsushima) who is the sister of his friend from 15 years ago. A bond is formed and they struggle with emotions that come about...