Police Lieutenant Matt Carson, Kenne Duncan and his associate, Sergeant Randy Stone Duke Moore, arrive at a park crime scene where a young woman lies dead in her underwear. They study the body and recall similar park murders, suspecting a link to the local “smut picture racket.” The case grounds their days in a grim pattern, as they search for the thread tying a string of crimes together.
In the studio of pornographic director Jaffe, Johnny Ryde Carl Anthony delivers orders from their boss Gloria Henderson Jean Fontaine. The staff scramble to protect their inventory, and Jaffe Harry Keaton promises to relocate the material after finishing that day’s shoot. Almost immediately, the police raid the studio, arrest everyone, and seize all the films and pictures, sending shockwaves through the operation and leaving the criminals reeling.
Carson and Stone are chastised by their superior, who demands swifter action to expose the racket. A local businessman, Mr. Romaine Harvey B. Dunn, stops by to question why taxpayers’ money is spent prosecuting pornography. He argues it’s harmless compared to juvenile gangs and violent crime, but Carson remains convinced that the dirty picture racket is connected to major crimes. He shows Romaine photographs of the murder victims and explains the disturbing chain between their exploitation and the deaths. Shaken, Romaine leaves with a wary sense of the city’s moral lines.
Gloria Henderson’s world tightens as she’s visited by Johnny Ryde, who informs her of the police raid. Their conversation reveals that the woman who opened the film’s murder arc was killed by their lackey Dirk Williams Dino Fantini for trying to blackmail Gloria. Johnny tells Gloria he fears Dirk’s volatile appetite for killing, while Gloria worries about the teenage customers demanding newer bondage photos.
At Jake’s Pizza Joint, teenagers mingle and brawl outside while Dirk Williams surveys from a distance. Inside, Jake negotiates for more smut pictures from Janet, an agent of the racket. He laments the dwindling inventory and presses for fresh material, asking Janet to hold onto the old photos until a trade can be arranged. Dirk tires of the street drama and calls the police before slipping away. When officers respond, they discover Jake’s smut stash and arrest him along with the two brawling men—rival smut peddlers vying for Jake’s business.
Gloria’s house becomes a late-night screening room as she and Johnny watch 16 mm films and discuss Dirk’s instability. Gloria notes that Dirk’s fixation with pornography seems to trigger his murderous impulses, while Johnny insists he can still keep the killer under control. Dirk, meanwhile, returns to the park and flirts with a woman before stripping her and stabbing her to death, escalating the threat he poses.
In the police station, Carson and Stone contemplate the kinds of women drawn into pornography rackets. A young woman named Mary Smith Jeanne Willardson becomes the focal point of their investigation. Unable to find legitimate film work, Mary agrees to work for Johnny Ryde and, after a hostile audition with Gloria, becomes entangled with Jaffe’s studio. She is later murdered in the park by Dirk, who finds her photos after breaking into Gloria’s house. Dirk’s fingerprints reveal his identity, and with his name in the papers, Gloria’s Syndicate pays a visit to demand Dirk’s murder before he causes more trouble.
Gloria wants Dirk silenced, but Johnny suggests a staged accident—sending Dirk on a car errand with faulty brakes so it appears to be a fatal crash. The next day, Dirk stalks another potential victim, a woman who turns out to be Officer Kline Fred Mason in disguise on orders from Carson. Kline subdues him, but Johnny arrives in the nick of time and knocks Kline out. Dirk realizes he must flee town, escaping in a car that eventually bucks the faulty brakes and allows him to leap out alive.
Dirk makes it to Gloria’s house, where he ambushes Johnny and reaffirms his status, insisting he deserves a seat at Gloria’s table. Dirk hides outside as Gloria returns and confronts him with the truth that Dirk is still alive. Johnny urges Gloria to meet his Syndicate contacts, but Dirk’s presence has already pushed Gloria to act. She returns with a plan, only to shoot Dirk in the darkness, mistaking him for Johnny. She phones the police to craft a story about Dirk shooting Johnny and fleeing, but the authorities break the ruse and arrest Gloria as the bodies of Johnny and Dirk are finally discovered.
