Riki holds in his hand a legendary student bag filled with steel plates. Carrying this bag meant that Riki was the target of hardcore delinquents while demonstrating to those around him that he was the strongest student. However, Riki has found no reason to shake his iron fist at them since his encounter with Yurina, who rejects senseless violence.

One day, Kunio rescued a student, Kurebayashi, who was not feeling well on the street. Kunio's heart flutters at the sight of her dainty appearance and sexy behavior, but Kurebayashi turns out to be a Red Lion, an assassin sent by the Kanto Lion Union, a gang of delinquents led by the Lion King. It was Misuzu, the female guardian of Taiyo High School, who first sensed Kurebayashi's ruse.

The straight-laced Kunio is always determined and always solves everything with one word: "Nekketsu". Misako, however, is not so sure about her future. With Hakuo's encouragement, Misako decides to enter a newcomer audition organized by a famous music producer Onishima, aiming to become a singer, which has always been her dream.

There was a series of disturbing developments around Kunio. Riki, Tadokoro, and Riki's senior, The Blue Emperor, were attacked by someone one after another. It was all the work of Sabu, a member of the Kanto Sanwakai, who was after Kunio's white uniform. Driven by remorse, Kunio vows to avenge Riki and the others, and gradually loses himself in anger.