During the year 2017, Takemichi Hanagaki, portrayed by Takumi Kitamura, finds himself in a dire situation when he learns that his former middle school girlfriend, Hinata Tachibana played by Mio Imada, and her younger brother Naoto Tachibana, acted by Yosuke Sugino, have fallen victim to the notorious Tokyo Manji Gang (also known as Toman). This distressing revelation leads to a life-threatening incident where Takemichi is pushed onto the train tracks, leading to an extraordinary twist of fate as he is transported back 12 years to 2005.
Revisiting his middle school days, Takemichi encounters Naoto and shares crucial information about the impending deaths of Hinata and Naoto. Upon shaking hands, an unexpected time paradox occurs, allowing Naoto to survive and become a detective in the present timeline. With Naoto's deduction that each hand-holding session enables Takemichi to travel back, Takemichi makes it his mission to change the past and save Hinata.
Returning to the past, Takemichi finds himself confronted with a harsh reality, where his friends are coerced into violent underground matches manipulated by a gang member named Kiyomasa played by Nobuyuki Suzuki. As Takemichi stands firm in his resolve to protect them, he earns the respect of the formidable gang leader Manjiro Sano, a.k.a. "Mikey," brought to life by Ryo Yoshizawa. However, the weight of the situation becomes painfully clear when Takemichi discovers that by forging a bond with Mikey, he inadvertently prevented his friend Akkun, portrayed by Hayato Isomura, from facing imprisonment in the present. Tragically, Akkun's overwhelming fear leads him to take his own life, leaving Takemichi to comprehend the true dangers posed by Toman.
As the plot thickens, Takemichi travels back to identify an escalating conflict in which the Tokyo Manji Gang declares war on their rival gang, Moebius, to avenge the honor of Pah-chin's friend. He quickly learns that Mikey's trusted second-in-command, Ken Ryūgūji, known as "Draken" and played by Yuki Yamada, is destined to meet a grim fate that will push Mikey towards violence and turmoil. While Draken survives a brutal clash, Pah-chin's decision to turn himself into the police after fatally wounding Moebius' leader ignites infighting within Toman, revealing the dangerous pitfalls of gang loyalty.
In a pivotal moment, Takemichi adeptly mediates the conflict between Mikey and Draken, but the stakes heighten as the Tokyo Manji Gang comes under siege on August 3, 2005. The gang is viciously attacked by Moebius members spearheaded by the scheming Shūji Hanma, portrayed by Hiroya Shimizu. It becomes evident that Peh-yan has allied with their foes out of resentment for how Mikey and Draken handled Pah-chin's situation. The tension escalates when Kiyomasa's aggression results in a serious injury to Draken.
In a climactic showdown, the Tokyo Manji Gang ultimately prevails, with Takemichi defeating Kiyomasa and ensuring that Draken receives the necessary medical attention. Following the turmoil, Peh-yan comes to terms with his mistakes and expresses remorse for his earlier actions. After all the chaos and countless struggles, Takemichi makes his way back to the present timeline, leading him to Hinata's home to reunite with Naoto, where he finally gets to meet Hinata, bringing his emotional journey full circle.
