Frank Serpico is an idealistic young New York City police officer who is determined to work without engaging in the corruption that plagues the department. His unorthodox appearance and attitude set him apart as he starts his career in plainclothes law enforcement, making his way through different precincts. Dedicated to law enforcement, Serpico is soon appalled to discover that the rampant corruption among the police force is not just a matter of a few bad apples but is systemic in nature, with payoffs and kickbacks being the norm. His refusal to take bribes and participate in the corruption isolates him from his fellow officers, creating tension and making him a pariah in the force.

As Serpico's journey within the force continues, he finds himself facing an increasingly hostile environment. The nonconformist officer's commitment to integrity leads to his active pursuit of justice against the culture of corruption. This crusade puts him at odds with his peers and his superiors, endangering both his career and personal safety. Despite the risks involved, Serpico remains undeterred in his mission to uphold the law and expose the corruption that undermines the very foundation of the police force. His solitary fight for truth and justice challenges the complicity and silence of those around him, setting the stage for a conflict that tests the limits of his resilience and idealism.