It's the athletic festival. Kakeru hurt his ankle during the pole-toppling game, and hid that fact from everyone else. Kakeru tries to keep his suffering to himself, when Suwa and the gang call out to him. Met with everybody's kindness, Kakeru begins to tell them what he's been keeping pent up inside. And then, the class relay begins.

It’s the spring of Naho’s second year in high school, and Naho receives a letter from herself, 10 years in the future. The letter accurately depicts what’s about to happen, including details on a transfer student from Tokyo, Kakeru Naruse, who ends up sitting beside her in class. On top of that, the letter also begs Naho not to invite Kakeru out with her group of friends on that day alone, but why?

After causing a catastrophe in the New Year’s Tournament, Jyugo and Musashi are sent to the underground cell. To solve the mysteries of their powers, Kenshirou suggests allowing the two to speak to one another. Unable to move freely, Musashi gives Jyugo information on the man with the scar.Listening to their exchange, Hajime tells Jyugo he’s empty. Hajime’s words confuses Jyugo.

The shackles have been triggered and Jyugo’s hands transformed into blades. He attacks Musashi and splits the arena in half. The arena becomes chaotic and Momoko orders Hajime, Kenshirou, Samon, and Kiji to apprehend Musashi and Jyugo. Musashi retaliates against the guards while Hajime stands in Jyugo’s way.

Tsukumo heads to the visiting room during the break from the New Year’s Tournament. His manager, Hattori, has come to visit. People think the famous action star is missing and has no idea he’s in prison. Hattori persuades the talented Tsukumo to come back into stardom. However, already uninterested in being a star, Tsukumo talks about his upbringing.

Cell 13 has advanced their way to the final event of the New Year’s Tournament. Jyugo and Hajime are battling against the Building 4 supervisor, Kenshirou Yozakura, and an inmate named Musashi. Jyugo is surprised to see Musashi again. Musashi, in search for the “man with the scar on his neck,” attacks Jyugo mercilessly. Soon as Jyugo hears about the man with the scar on his neck, something odd starts happening to his body.

Jyugo and the gang are advancing through the New Year’s Tournament without a hitch. In the Hyakunin Isshu event, Uno wins against the Building 3 inmates, Trois and Honey. The 4th event is a physical match revolved around a spinning top, but Niko unintentionally enters the match. The opponent is Upa, a kung-fu expert from Building 5. Does Niko, the otaku, have any chance of winning?!

Nanba's New Year Joint Cooperation Tournament, aka New Year’s Tournament, begins by gathering the entire inmates. Jyugo and the others are enthused once they hear the winner gets to choose whatever he wants. However, all the matches are odd events relating to New Year’s. Can Building 13 win against the other inmates led by peculiar guards?

Jyugo and the gang are killing time teasing the new guard, Seitarou. One day, a new inmate is sent to Cell 13. Inmate Number 99, Tsukumo. He looks and acts like a ninja! Uno, Niko, and Rock are excited to see the real thing. But as a Japanese, Jyugo does not believe him. To convince Jyugo that he’s a true ninja, Tsukumo challenges Jyugo to see who can escape from prison...

Jyugo heads toward the cell Hajime is trapped in on his own. In the underground level 2, Uno, Trois, and Honey are looking for a certain guard relying on the smell. Enki finds out Jyugo and the others have escaped. Bruised all over, Jyugo finally reaches to Hajime’s cell on level 5. However, Hajime says something very heartless to Jyugo.

Jyugo, Uno, Nico, Trois are attacked by Ruka’s powerful weapon, Bashosen. Honey tries to fight him off, but at this rate, all four will perish. Trois tells Jyugo and Uno to go ahead of them while they fight Ruka. Uno takes Jyugo’s hand and run towards the stairs. But Jyugo is concerned about Honey and Trois who are fighting for them...

Jyugo and the others continue to run from Ruka’s attack. But Honey tells Jyugo not to follow them because he believes Jyugo’s only in their way. Jyugo starts to self-reflect from Honey’s lecture and starts revealing about himself to Uno. However, Ruka is quickly approaching. Jyugo and Uno are saved by someone unexpected.

Beating Hachiman, Nico, Liang, and Upa moves ahead guided by Qi. Upa feels someone other than Enki is involved in the incident. Jyugo, Uno, Honey, and Trois reaches level 3 underground. They encounter Ruka Gojyou, a former Building 5 guard who has escaped from his cell. Ruka, along with guards, Youriki and Kokoriki, attacks Jyugo’s party. Running away from Ruka, Honey starts getting irritated at the incompetent Jyugo.

The medication completely gone from his system, Nico suffers and goes berserk. Wanting his medicine, Nico attacks Hachiman. Upa and Liang is surprised to see Nico in that state. Then, the traitor, Qi, appears. Qi understands medications can turn into poison if they’re not handled properly. He remembers the days when Hachiman used to treat him like a tool along with Upa and Liang.

The escaped convict, Hachiman, appears in front of Liang and Upa. Nico has remained with them to help. Hachiman, former boss of Liang and the others, uses a large weapon and poison to attack. That poison was provided by Qi, who has betrayed Building 5 and joined Hachiman. Meanwhile, Uno and Jyugo are concerned about Nico, who doesn’t have his medication. It seems something horrible will happen to Nico is he doesn’t take his medicine...

The inmates in Cell 13; Jyugo, Uno, Niko, and Rock are spending their days escaping, creating mischief, gossiping, and sometimes, working. These troublemakers are giving a headache to supervisor of Bldg. 13, Hajime Sugoroku. Warden Hyakushiki has ordered Hajime to submit files regarding the 4 inmates. Hajime is then ordered to give a report about the 4 who are known as repeat offenders of jail-breaking. Afraid of losing his job due to the cover-up, Hajime does his best to create the new files...

Jyugo, Uno, Nico, Liang, Upa, Honey, and Trois make their way through Building 5 underground cell to find the captured guards. They hide in the file room and Jyugo finds document about himself and finds a shocking information. The group encounters a Building 5 guard, Rokuriki, who is under someone’s control. Liang and Upa tells Jyugo to keep going while they take care of Rokuriki.

Hajime, Jyugo, Uno, and Nico head to Building 5 to find out about Rock and Yamato. Jyugo and the others fall into a trap and end up in level 1 underground cell. There, they find the captured Upa and Liang. Meanwhile, Hajime is captured by Inori and is escorted to the underground cell where Samon, covered in injuries, is restrained. Samon reveals who’s behind the incident. It is no other than Enki Gokuu, the former Building 5 supervisor who became a criminal causing havoc in Nanba Prison in the past. He is also Samon’s brother.

Rock and Yamato suddenly become violent after returning from Building 5 and attack Jyugo and Seitarou. Covered in bruises, Jyugo tries his best to protect Uno and Nico. Tsukumo, who has been training in Building 5 with Rock, appears. Hajime knocks out Yamato and realizes a familiar yellow talisman on the nape of Yamato’s neck.

Yamato takes Rock and Tsukumo to Building 5 for training. Rock challenges Samon to a duel, but he is defeated by only one finger. The warden gathers all the supervising officers before she leaves for her business trip. Nimaijita, the deputy supervisor of Building 2, blames Samon that Nanba Prison’s reputation is ruined because of what happened in Building 5 in the past. Unable to take it any longer, Samon leaves the room. This is because someone important to Samon is related to this incident.