The city of Shibuya is home to several groups of gangs but none is more feared or respected than the group Zero. They use their power to keep peace between the other gangs and prevent all out wars from going on. The leader of Zero is Kiryuu Tatsuya, a living legend and who is said to be the strongest man in Shibuya.
Fujimura Shintarou just came out of juvenile hall in Nagano, after 3 years when he nearly killed the man who murdered his friend. Shintarou is a founding member of Zero with Tatsuya and as his nickname, "the dinosaur of Shibuya," might tell, his power rivals that of Tatsuya's. But coming out a changed man, Shintaro tries to start a life outside of Shibuya. But when he learns his long time friend is trying to use Zero to take full control of Shibuya, he gets dragged back into the world of street gangs.