- The late 1960s, young man who spends his days brawling and stealing drifts into a Tokyo flophouse district. His name is Joe Yabuki (Tomohisa Yamashita). There, he meets alcoholic former boxer Danpei Tenge (Teruyuki Kagawa), who senses a natural born fighting talent in Joe. However, soon after Joe is sent to a reformatory for assault.
Danpei sends Joe a letter while he's incarcerated. Entitled "For Tomorrow", it explains the basic boxing technique of the jab. Even inside, joe stirs up trouble and gets into fights during which he encounters a powerful, champion-level pro boxer named Rikiishi (Yusuke Iseya). During their battle Joe throws his half-baked jabs but suffers defeat for the first time in his life. In order to beat Rikiishi, Joe begins a strict training regimen through his correspondence with Danpei.
One day, Joe is paid a visit by the daughter of the Shiraki Consortium, Yoko (Karina). She proposes a boxing tournament in the reformatory, pitting her family-owned gym's fighter Rikiishi against Joe.
The match with Rikiishi proves punishing for Joe, but by using the cross-counter knockout punch taught to him by Danpei, he courageously manages a draw. After their release from incarceration, Joe and Rikiishi both progress as professional boxers in their respective weight classes. Despite being new to the ring, Joe becomes a popular bantamweight fighter known for his "no guard" style. Rikiishi makes his way to the top of the featherweight class and a chance at a title bout while Joe crushes a string of formidable opponents.
Determined to face off Joe, Rikiishi begins a severe weight loss regimen to drop down to Joe's weight class.
Joe vs. Rikiishi - the ring of the bell sounds their destiny!