Yoichi Mori, a member of the gang Ame-gumi, is at odds with Boheta, the young leader, over the management policy of the gang, and starts a new organization, the "Kyokudo Daigaku-gumi," together with his friend Shun Akiba. Yoichi tries to find the murderer of the previous head of the Ame-gumi and repay his late predecessor's kindness, while Boheta tries to eliminate the Gokudo Daigaku-gumi with a trap and assassins, even involving the police. Meanwhile, the Daigaku-gumi also expands its organization by "enrolling" delinquent youths and boys. The battle between the Daigaku-gumi and the Ame-gumi eventually develops into a large-scale war with the Ame-gumi's upper organization, the Hotarukai.