Newcastle-born gangster Jack Carter has spent years navigating the treacherous waters of organized crime in London under the watchful eyes of crime bosses Gerald and Sid Fletcher. However, a web of deceit and personal betrayal unravels when Jack becomes entangled in an affair with Gerald's girlfriend, Anna, while also plotting their escape to South America. He finds himself compelled to return to Newcastle to attend the funeral of his brother, Frank, whose death was announced as a drink-driving accident, but Jack's instincts tell him that there’s more to the story than meets the eye. Despite warnings from his bosses to tread lightly, Jack's determination to get to the bottom of his brother's demise leads him down a perilous path.
At the funeral, he reconnects with his teenage niece, Doreen, as well as Frank's secretive mistress, Margaret, both of whom hold key pieces to the puzzle he is trying to solve. Seeking answers, Jack heads to Newcastle Racecourse with the hope of finding his old acquaintance, Albert Swift, but is met with evasion and denial. Jack's relentless pursuit of the truth brings him closer to dangerous figures, including an old associate, Eric Paice, who remains tight-lipped about his connections.
When Eric eventually leads Jack to the estate of crime boss Cyril Kinnear, Jack confronts the man, but the encounter yields little information. Here, he also meets a strikingly glamorous yet inebriated woman named Glenda, who unwittingly becomes part of Jack's turbulent journey as he is warned against creating a rift between Kinnear and the Fletchers. The pressure mounts when Jack faces threats from henchmen urging him to leave town, only to retaliate fiercely and capture one of them for interrogation, uncovering the name "Brumby."
Understanding Brumby to be a businessman with ties to local seaside amusements, Jack's visit to confront him leads to more confusion than clarity, as Brumby claims ignorance of Jack's connection to Frank. Meanwhile, two associates dispatched by the Fletchers—Con McCarthy and Peter the Dutchman—arrive in Newcastle to retrieve Jack, but he deftly evades capture. A fateful meeting with Margaret to discuss Frank soon has Jack on the run again, but Glenda swoops in to rescue him in her sleek Sunbeam Alpine sports car. At this point, Brumby divulges Kinnear's involvement in Frank's death, tempting Jack with a £5,000 offer to take out the crime boss, which Jack firmly declines.
The tension escalates when Jack discovers a pornographic film titled "Teacher's Pet" featuring Doreen, prompting a violent confrontation with Glenda, who reveals that Kinnear likely coerced Doreen into that twisted production. In a moment of rage, Jack forces Glenda into the trunk of her own car before setting off to find Albert once more. Upon tracking him down, Albert confesses to misleading Jack, ultimately revealing a conspiracy linked to Frank's death orchestrated by Eric and Kinnear.
In a climactic turn of events, Jack's vengeful arc culminates in the brutal murder of Albert, followed by a violent shootout with Eric and the London gangsters, resulting in Peter's death at Jack's hands. The dust settles on a sequence of revenge that sees Jack viciously exacting payback on Brumby before disposing of the damning film by sending it to Scotland Yard.
With the stakes higher than ever, Jack abducts Margaret in another play to manipulate Kinnear. He offers Kinnear the film in exchange for Eric, but the plan spirals further into chaos as ulterior motives come into play. Jack's journey of vengeance reaches its zenith when he trails Eric along a desolate beach, forcing him to sip whisky in the same manner as Frank before delivering a fatal blow with a shotgun.
As Jack walks along the serene shoreline, triumphant yet tormented by the consequences of his choices, his reign of retribution meets a tragic end when he is shot from a distance by an associate of Kinnear. In this dark tale of betrayal, power struggles, and revenge, Jack Carter’s quest leaves an indelible mark on the unforgiving landscape of Newcastle's underworld.
