Watching the news, Hanagaki Takemichi learns that his girlfriend from way back in middle school, Tachibana Hinata, has died. The only girlfriend he ever had was just killed by a villainous group known as the Tokyo Manji Gang. He lives in a crappy apartment with thin walls, and his six-years-younger boss treats him like an idiot. Plus, he’s a complete and total virgin… At the height of his rock-bottom life, he suddenly time-leaps twelve years back to his middle school days!! To save Hinata, and change the life he spent running away, hopeless part-timer Takemichi must aim for the top of Kanto’s most sinister delinquent gang!!Takemichi Hanagaki’s life is at an all-time low. Just when he thought it couldn’t get worse, he finds out that Hinata Tachibana, his ex-girlfriend, was murdered by the Tokyo Manji Gang: a group of vicious criminals that has been disturbing society’s peace for quite some time. Wondering where it all went wrong, Takemichi suddenly finds himself travelling through time, ending up 12 years in the past—when he was still in a relationship with Hinata. Realizing he has a chance to save her, Takemichi resolves to infiltrate the Tokyo Manji Gang and climb the ranks in order to rewrite the future and save Hinata from her tragic fate.