"Mad Bull 2000" is a manga series that blends action, crime, and dark humor, set in a gritty urban environment. The narrative centers on John Estes, a rogue NYPD officer known as "Mad Bull," who operates outside conventional law enforcement to combat crime in New York City. Estes is a brutal and unorthodox cop, often resorting to extreme violence and questionable methods to achieve justice. His partner, Daizaburo "Eddie" Ban, a young Japanese-American officer, serves as a counterbalance, providing a more measured and ethical perspective. Together, they tackle a variety of criminal elements, from street gangs to corrupt officials, navigating a world where the line between right and wrong is often blurred.

The series explores themes of vigilante justice, corruption, and the moral ambiguities of law enforcement. Estes' relentless pursuit of criminals often leads to chaotic and over-the-top confrontations, with the narrative frequently emphasizing the absurdity and excess of his methods. Despite his violent tendencies, Estes is portrayed as a complex character with a deep sense of duty and a personal code of honor. Eddie, on the other hand, struggles with the ethical implications of their work, often questioning the morality of their actions while trying to maintain his own integrity.

The plot is episodic, with each chapter or arc focusing on a specific case or criminal organization. These stories range from high-stakes drug busts to personal vendettas, often intertwining with the characters' backstories and motivations. The series does not shy away from graphic violence, dark humor, and social commentary, often highlighting the systemic issues within the criminal justice system and society at large. The dynamic between Estes and Eddie drives much of the narrative, with their contrasting approaches to justice creating tension and growth throughout the series.