After an accident on his scooter, Yuusuke Serizawa awakes to find himself in a hospital bed. The cause of the accident—the sight of a familiar face that distracted him. However, it turns out that the person who distracted him was also the person who called the ambulance for him, and whoever it was won't reveal their identity. All Yuusuke knows is that this person is a woman from his past—someone that he loved and possibly wronged. Now Yuusuke must search his memories of the women in his life to discover the identity of his guardian angel. Will Yuusuke be able to find the true identity of this woman and rekindle the flame of a past love or will this woman forever remain a mystery, lost to old memories? (Source: Kodansha USA)