Hiroya Munakata is the leader of the yakuza group Munakata-gumi. After 10 years since the big fight, Hiroya Munakata's non blood-related younger brother Takashi is released from prison, but Takashi’s daughter, Hyuga says she does not want to meet her father and runs away from home. Hiroya, Takashi and Hiroya’s subordinate Shinya go to Zeni Island where Hyuga is headed to. Something they never expected is waiting for them.

"Drop" tells the story of a boy named Hiroshi Shinanogawa, who grew up in the 1980s. He became inspired by the Be-Bop High School manga and decided to become a delinquent. Hiroshi dropped out of a private middle school and transferred to a public school There he joins up with a delinquent gang.