It is 2017, and Budo Hanagaki, a 26-year-old freelancer living a life at the bottom of the barrel, sees the news that his junior high school girlfriend, Hinata Tachibana, has been killed in a war with her brother Naoto by the criminal group Tokyo Manjikai (To Manji). The next day, on his way home from a part-time job, someone pushes him onto a train platform, and as he prepares to be run over and killed, he is sent back in time to 2005, 12 years ago, when he was at the peak of his life.