Yukio, who is also known as Yuki, and his friend Tetsushi, or Tetsu, operate in a city ruled by gangs. To earn a living, they sell fake drugs in alleyways. However, when Yuki's younger brother falls ill and requires hospitalization, they are forced into a desperate situation. In a bid to get untraceable cash, they plan to rob the vault at the Seidoukai headquarters, a notorious Yakuza gang.
Their plan fails, but Yuki captures the attention of an influential boss, Kazutaka Hyodo. Hyodo agrees to pay for Yuki's brother's medical expenses and let them go free. However, there is a catch: Yuki must visit Hyodo's office alone once a week without fail. Despite the risks, Yuki prioritizes his brother's health and agrees to the terms. Meanwhile, tension increases between the Seidoukai and a rival gang that is vying for power.
