Writer Jimmy Breslin begins the film by narrating the story of New York City's current wealth, juxtaposed against its past turmoil. He recalls the news from 1977 regarding the infamous .44 Caliber Killer and illustrates how the city was once in a severe state of decline. He quotes, > "there are 8 million stories in the naked city, and this is one of them."
The film opens with a grim apartment where a man is desperately yelling to stop a relentless dog barking. In a shocking turn of events, he storms out and shoots two girls who are conversing in a parked car. We then shift to Vinny (John Leguizamo) and his wife Dionna (Mira Sorvino) as they head to a nightclub to enjoy some dancing and camaraderie with friends. Their routine is interrupted when Dionna's cousin requests a ride home. Vinny takes this opportunity to sneak off with her, hiding his ulterior motives from Dionna. Just as they engage in an intimate moment, they are spooked by another couple's arrival, forcing them to flee. Unbeknownst to Vinny, the killer emerges and takes care of the couple.
Driving Dionna home, she senses something is amiss and probes Vinny about his prolonged absence. He claims he had to relieve himself, but as fate would have it, they arrive at the crime scene from earlier. Utterly shocked, Vinny realizes the victims were indeed the couple who interrupted him, leading him to vomit in horror upon returning to the car. He warns Dionna about the .44 Caliber Killer, now dubbed the Son of Sam. Concern escalates when Vinny's friends—Joey T, Brian, and Anthony—joke about how the killer might have spotted him and will come for him next. Although they jest, the fear begins to settle in Vinny's mind.
In a punk fashion, Ritchie (Adrien Brody) arrives to the group, earning skepticism from most except Vinny. When Ruby (played by Jennifer Esposito) joins, fresh from a breakup, she immediately takes an interest in Ritchie's edgy style. Meanwhile, at Dionna's father's restaurant, local mob boss Luigi (Ben Gazzara) is approached by a detective regarding the killer case. Although he rebuffs the request for assistance initially, he changes his mind after reading a chilling letter from the Son of Sam, which leads to a sense of urgency to catch the murderer.
As the narrative unfolds, we see Ritchie facing personal struggles, and Vinny entangled in his guilt, dabbling in an affair with his boss Gloria. Amidst local panic spurred by the killer's letters and rising tensions, Luigi sets up a block party to unite the community against the fear, while Joey T and the boys patrol the streets, aggressively confronting any possible suspects. The plot thickens as Vinny and Dionna drift apart, culminating in a fierce argument leading to her departure.
With July 29 drawing near, Joey and his gang begin acting preemptively against their own list of suspects, unaware of the true Son of Sam lurking among them. Vinny stands up for Ritchie even while experiencing mounting doubt and paranoia about his character. Vinny's spiraling behavior ultimately pushes away the people he cares about, leading him deeper into drugs and despair.
Just as things seem to spiral out of control, the police apprehend the actual David Berkowitz, closing a chapter filled with terror and confusion for the residents of New York. Vinny, conflicted and regretful, faces Ritchie one last time, attempting to express his remorse amid the chaos that ensued. The film concludes as Jimmy Breslin recaps the significant events of the summer of 1977, reiterating once more, > "there are 8 million stories in the naked city, and this was one of them."
