Boxer Nao Dorokawa, who is preparing for the preliminary round of the world championships, spends her days enduring intense training at a crumbling boxing gym. In contrast, Nao's rival, Aika Hijirikawa, the daughter of a wealthy conglomerate, has been trained in a privileged environment and is an influencer everyone loves. The two, who have contrasting backgrounds and personalities, clash in the ring, but an unexpected tragedy awaits them beyond their match.

Nao's life as an athlete is suddenly cut short, and she is unable to accept the reality of her situation and is in a state of desperation. Her nurse, Miyazaki, tries to be kind to her, but Nao rejects her attempts. Meanwhile, Hugo and Shawn learn of Nao's accident and secretly attach a prosthetic leg they made to her leg. Nao is bewildered by the unknown prosthetic leg, but she begins to walk desperately while enduring the pain, fed by her fighting spirit against Aika.

Hoping to return to the ring as a boxer with a prosthetic leg, Nao visits Masaharu, who has not been seen at the hospital since her hospitalization, and hopes that he will continue to train her. However, Masaharu, who sees no hope for Nao's recovery, gives up on her and brings in a young girl as a new promising athlete. Furious at his betrayal, Nao gets into a fistfight with him. Meanwhile, a mysterious woman named Ran arrives at the hospital.

When Ran informs Nao of her origins, she is touched by her affection and her hardened attitude gradually softens. Later, Nao is taken by Ran back to her birthplace, where she is reunited with her father, Shion, who is living under Ran's care. Feigo and Shawn, concerned for Nao's safety, have been exploring the inside of the Dorokawa household for some time, and are relieved to see Nao spending time with her family. However, something unusual happens to her when she regains her childhood memories.

Nao is brought to the garage where Feigo and Shawn live and she meets Ace, the leader of the two, and Tachibana, who is arranging illegal jobs for them. Hoping for a rematch with Aika, Nao approaches promoter Nunobe for advice but is told that a large amount of money is needed to run the show. With Tachibana's suggestion, Nao begins to engage in a part-time job behind the scenes, but during her work, she becomes involved in an incident, which leads her to confront Ace.

Ace sees Nao's fighting spirit and encourages her to enter the underground martial arts arena. However, Nao, who is determined to re-establish herself as a boxer, rejects his offer. She then gives Nunobe all the money she has saved for a rematch with Aika, but her hopes are unexpectedly betrayed. As if to push Nao into a corner, Aika wins the world champion's title. Ace and his friends take Nao to a place for her, where her path to a comeback is blocked at every turn.

Having lost hope for the public stage, Nao decides to enter an underground martial arts ring. However, the audience has low expectations for Nao, who wears a prosthetic leg. She wants to change her reputation, but she is outmatched by her opponent, Ando. Meanwhile, detective Gunsawa visits Aika's father, Seichiro, regarding the hit-and-run incident involving Nao. Meanwhile, Aika and Gan begin to take action to create a system to wipe out evil people from the world.

Nao is steadily making a name for herself in underground martial arts when she meets a girl named Ko Ko Koi, whom Ace has been taming to use as a blackmailer. Meanwhile, the warehouse where the underground martial arts are practiced has been sealed off, and Tachibana has evicted Nao and her friends from the garage where they have made their home, leaving them with no place to go. Aika and Gan's activities provoke an unexpected response, and many supporters show up. Aika and Gan's "justice" ironically leads Nao's destiny to become even more deranged.

Aika and Gan's activities steadily bear fruit. Meanwhile, Nao and her friends celebrate Ko Ko Koi's birthday at the burglarized mansion. The peaceful days continue for a while, but Aika and Gan, learning of Nao and the others' crime, show up and force them to flee from the mansion they have been using as their base of operations. Later, Aika learns of a certain fact from a conversation between Detective Gunsawa and her father, Seichiro, and her emotions are violently shaken. Meanwhile, Nao and her friends are confronted by someone who wields a warped sense of justice.

After taking the injured Ace back to their hideout, Nao and the others learn of the salon Aika and Gan have set up and realize that they are being targeted. Meanwhile, Aika and Gan denounce the crime committed by Shinji, a fan of Aika. As a result, Shinji, feeling shunned by Aika, goes berserk and appears before Nao and the others. Nao learns the truth about the accident that drove her to the brink of despair, and she confronts Shinji with her anger.

As Shinji's arrest shocks the public, Aika, feeling responsible, announces at a press conference that "Yatter 1", which she launched with Gan, will be disbanded. Aika apologizes to Nao through the media, but Nao, who believes that Aika is the culprit behind everything, is angry at her words. She, together with Hugo and Shawn, kidnaps Gan and lures Aika away. With neither of them able to take a step back, Nao and Aika once again exchange fists.