In 2017, Takemichi Hanagaki learns that his middle school ex-girlfriend Hinata Tachibana and her younger brother Naoto have been murdered by the Tokyo Manji Gang. On his way home from work, he is pushed onto the train tracks and suddenly travels 12 years back to the past. That night, he saves Naoto from several bullies and tells him about his and Hinata's impending deaths. After they shake hands, Takemichi returns to the present to find that Naoto had saved him, creating a time paradox where he is alive and a police detective.