A former boxer and current drunkard named Danpei Tange meets a drifter named Joe Yabuki and sees potential in him. Tange offers to teach Joe how to box, but Joe isn't easily convinced.

Danpei is severely hurt after trying to protect Joe from the yakuza. Joe goes to visit the head of the yakuza group to try to get reparations for Danpei.

Danpei works hard day and night to save up for Joe and his boxing gym. Meanwhile, Joe uses the slum kids to con some money out of people and he runs into a woman named Yoko Shiraki.

Joe holes up in an abandoned building after he gets caught lying to con people out of money.

Tange sends Joe a letter to teach him boxing while he's at the police hospital waiting for his fate.

Joe ends up in a juvenile classification home and is quickly put into his place after trying to be cocky against his fellow inmates and their boss Nishi.

Joe, Tange, and the kids show up to court to hear if Joe will be sent off to the juvenile training school.

Joe and Nishi spend their first night at the Toko Special Juvenile Training School and are quickly put into their places.

Joe and Nishi are sent out with the rest of the inmates to do some farmwork. Later on, Nishi comes up with a plan to help Joe escape the island, but they meet a man named Toru Rikiishi.

Joe is completely out of it after getting punched by Rikiishi. However, later on, he had a huge surprise in store for everyone.

Joe continues to practice boxing while he's alone in solitary. Danpei and the kids try to find a way into the juvenile training school when they unexpectedly run into Yoko.

Joe tells Yoko why he treats her so badly. Rikiishi tries to interfere and Yoko proposes that they settle this in a boxing match. Tange finally gets to train Joe again in person.

Joe and Rikiishi prepare for their upcoming match. After seeing just how powerful Joe's new punch is, Rikiishi devises a unique training method to counter it.

Joe and Rikiishi finally have their first match. But for some reason, Danpei tells Joe to let Rikiishi keep knocking him down. Who will be the winner in the end?

Moved by the fight between Joe and Rikiishi, the inmates also start boxing.

Tange becomes the full-time boxing coach at the juvenile training school on Nogiku Island. Joe seems to finally be interested in training more with Tange, but Tange suddenly seems distant.

Joe keeps trying to get Tange to coach him again, but Tange just keeps ignoring him and concentrates on training Aoyama. No one expected Aoyama to get into the tournament, but he then somehow defeats the rep for dorm 7, Numata.

The dormitory boxing tournament begins and everyone finds out just how Aoyama defeated Numata.

Joe and Aoyama's match finally begins, but who will come out on top?

Joe and Aoyama's match concludes and Tange reveals something to our two fighters.

Rikiishi tells Joe that they need to have their match sooner because something came up, so they have an unofficial match out in the rain.

Rikiishi leaves Toko Special Juvenile Training School and Joe feels empty inside. Meanwhile, the final match of the dorm boxing tournament is about to begin.

Following Rikiishi and Aoyama, Nishi is also going to leave the juvenile training school, leaving Joe all alone.

Joe finally leaves the juvenile training school and goes back to the slums where he's welcomed back with open arms, and Danpei has a surprise for him.

Joe finally feels like something might be changing in his life, but then he is visited by Guerilla, who's on the run from the police.

Tange goes to the Japan Boxing Association to get his gym officially recognized. Meanwhile, Joe starts working at the grocery store Nishi works at.