Frank Serpico is an idealistic young man who has just become the newest member of the New York City Police Department. He dreams of becoming a detective, hoping to qualify for the prestigious gold shield. He joins the Plainclothes Division, dressing like a hippy as part of the job, which is the source of much derision from his coworkers. As he continues his line of work, he will learn the disturbing reason behind their hostility.
The year is 1972 and a man named Sonny Wortzik stormed into the First Brooklyn Savings Bank along with two accomplices. Sonny is clearly inexperienced in the art of bank robbery, as the plan begins to go awry in a matter of seconds. One of his accomplices, Stevie, loses his nerve after Sonny produces his weapon and asks to be let out of the bank. To make matters worse, they have arrived after the daily cash pickup, leaving a paltry $1,100 in the vault. From there, the plan that should have taken ten minutes snowballs into spectacle entrancing the neighborhood and later, television viewers across the nation.