Takemichi Hanagaki lives as a 26-year-old freeter. His life is basically miserable. One day, he learns from the news that Hinata Tachibana and her younger brother Naoto Tachibana were murdered by the Tokyo Manji Gang. Takemichi Hanagaki is stunned by the news because Hinata Tachibana was his first love during his middle school days.
The next day, Takemichi Hanagaki is pushed by someone on a station platform and falls onto the railway track. At that moment, he goes back 10 years into the past. There, he tells Naoto Tachibana that in 10 years, Hinata Tachibana will get murdered. This changes the present day. Now, Naoto Tachibana works as a detective and avoids being killed by the Tokyo Manji Gang, but Hinata Tachibana's fate is different. She is murdered by the Tokyo Manji Gang.
Takemichi Hanagaki then asks for help from Detective Naoto Tachibana. He wants to save Hinata Tachibana by going back in time to destroy the Tokyo Manji Gang.
