The film opens with two Correctional Officers and Mark Brandon “Chopper” Read watching an interview that was conducted by Renée Brack for the latter being broadcast on a Television set in a Prison cell.

The scene then cuts to H Division, Pentridge Prison, Victoria, Australia, 1978. Mark is placed into a room with other cellmates, including an external group that uses the other half of the room. The man in charge, “Keithy George” (David Field) Whistles to Mark, stating that the line placed in the center of the yard is used to separate the groups and tells him to; “Stay on that side and we’ll stay over here”. After a brief verbal spat between Keithy and Mark, the scene cuts to Jimmy Loughnan (Simon Lyndon), Bluey Barnes (Daniel Wyllie) and Mark in their cells. Jimmy exclaims that Keithy’s in the Painters and Dockers, to which Mark replies that in prison, he’s just “another Bare bum in the shower.” Jimmy questions why they’ve been fighting with them for the past 3 years, to which Mark replies he doesn’t know. Jimmy states that there has to be a reason, to which Mark replies “We’ll make one”.

The next day, Mark enters the room and glances over to Keithy, rushing over towards him and horrifically stabbing him multiple times in the face and neck. In his anger, Mark paces off and proceeds to process his actions. Bluey calls out to the Correctional Officers; all the while Mark rolls Keithy a Cigarette and tells him that it’s going to be okay. After another brief verbal spat, Mark states that he’s the one who runs the Division. Correctional Officers soon enter the room and drag Keithy George out for medical treatment, Mark walks over to Bluey and Jimmy on the other side of the room, who are angered by what happened, knowing that there’ll be consequences.

The day following the attack, Mark is summoned to meet with two detectives; Detective Senior Sergeant Creswell (Caleb Cluff) and Detective Sergeant Wyatt (Hilton Henderson) from the Prison Liaison Office, who are investigating the attack on Keithy George. Mark states that no one in the room had any idea of who attacked Keithy George. Creswell informs Mark that Keithy died that morning of Exsanguination. Mark, Bluey, and Jimmy are seen in their cells, exclaiming that the Painters and Dockers will soon want to have Mark killed for killing one of their members. Mark is then met with Governor Beasley (Fred barker), who informs him that there’s a rumor that the Painters and Dockers have placed a contract on him worth $10,000. In his paranoia and effort to maintain dominance, Mark soon devises a plan to kidnap two Correctional Officers, claim siege to H Division and turn most of the inhabitants into Paraplegics, in response to the newly created contract. Bluey and Jimmy attempt to break away from the plan, knowing that it would be a suicide mission. Mark reminds Jimmy of what he’s done for him in the past and reminds Bluey of the first time that he met him, sulking and crying in a corner. Both parties agree due to intimidation.

Whilst pacing back and forth in their cell, Mark, Jimmy and Bluey discuss who will be participating in the Riot for control of H Division. Suddenly, Jimmy seemingly punches Mark’s stomach twice, before walking back a few steps while Bluey anxiously moving into the corner of the cell behind Jimmy. Mark looks down and soon discovers that Jimmy has shanked him twice, asking him what’s gotten into him, to which Jimmy stabs him twice more, all the while Mark standing still in awe. Jimmy soon tears up and apologizes for doing so, and stabs him twice more before Mark pins him up against the cell wall. Jimmy is disarmed and Mark removes his own clothes, revealing a body covered in blood. Mark begins to lose blood and collapses onto the ground, struggling to remain conscious. Jimmy rolls him a cigarette and they call out for the Correctional Officers, but not before Jimmy slashes his own arm to claim self-defense.

Mark soon awakens to Creswell and Wyatt, informing him that Jimmy has made a statement against him. Mark recovers and is returned to a separate cell from Bluey and Jimmy. Mark, Jimmy and Bluey exchange words over the walls about the future court case between Jimmy and Mark. The scene then turns to the court case, where it’s revealed that Mark is serving a 16 ½ year sentence for the attempted abduction of a Judge in order to give Jimmy Loughnan freedom. Back at the Prison, Mark’s picture is all over the newspapers and Jimmy is visibly annoyed by this, Mark’s celebration is cut short when members of H Division soon display their hatred for Mark over the Prison’s walls. Mark meets with Governor Beasley and other members of the Prison Board, attempting to negotiate a change of Prisons for security, which becomes unsuccessful. In response, Mark has a member of H Division cut his ears off to relocate to the mental health wing, in which he’s successful in doing, and serves out the remainder of his sentence.

The scene then cuts to 1986. Chopper is out of Prison and reunites with an old girlfriend of his, Tanya (Kate Beahan). The two spend the night drinking, ingesting and Injecting Heroin and having sex. Later on, Mark visits his Father, Keith Read (Kenny Graham). The two have a beer together and discuss Jimmy Loughnan, who’s apparently at large. Mark and Tanya later go to a club and share a few drinks, they soon run into Neville Bartos (Vince Colosimo), flaunting his wealth. Mark apologizes for the leg injury he had inflicted on Neville and the latter soon shouts the pair drinks. Mark overthinks the situation and confronts Neville about the injury. Later at the club, Mark runs into Sammy the Turk (Serge Liistro), and accuses Tanya of flirting with him after offering a light for his cigarette, this causes Mark to fly into a rage and forcefully take Tanya out of the club. On the way out, Neville makes an arrogant grin towards the pair leaving, to which Mark responds with revealing and firing a handgun off in the club multiple times. Outside of Tanya’s house, Mark apologizes for the evening and discusses moving away to Tasmania, to which Tanya laughs it off, infuriating Mark, who then accuses her of cheating. Tanya then heads inside, to which Mark heads inside soon after her. In the house, Mark catches Tanya on the phone with Neville and responds by physically abusing both her and her mother (Pam Western). Mark then storms out of the house.

Mark meets with Detective Downie (Bill Young) and Detective Cooney (Peter Hardy) at a bar, feeling ashamed that he’s letting them down. Not knowing what he’s talking about, informing Mark that they don’t condone his “Poetic Justice”. Mark Grins, salutes and unabashedly confirms that he understands perfectly what they mean. Mark later goes to Neville’s house; an angry and disgruntled Neville reluctantly lets him in. During the tour of the house, Neville feeds his dogs Cocaine. In the house, Mark enjoys free alcohol and Cocaine. It’s revealed that Neville is supplying most of the Western Suburbs of Melbourne, upon learning this, Mark begins to pressure Neville for money, insisting that he owes him. Mark then begins to count to 20. Ignoring Mark’s threats to produce cash, Mark shoots him once in the abdomen. Neville’s friends Robbo (Sam Houli) and Nick (Robert Rabiah) with Mark’s help then proceed to transport Neville to the Hospital. In the background, Downie and Cooney are questioning Mark over the shooting of Neville and rumors of him having arrangements with the police force to execute criminals with impunity, and it’s also revealed that there’s a contract out on him for an unknown amount.

Later, Mark heads to Jimmy Loughnan’s apartment. After a brief Frisking for weaponry, he allows him to enter. he also shares the apartment with his pregnant fiancée, Mandy (Skye Wansey), and their young Daughter Shazzy (Annalise Emtsis). The pair are plagued with Heroin addiction and are in financial hardship, Jimmy tells Mandy to take Shazzy to bed. After they exit the room, Jimmy and Mark begin to talk. Mark asks Jimmy if he’s employed and how much Heroin he uses. After a few sarcastic remarks, Mark reveals that he’s working for the Police, stating that he has a green light to conduct shootings on criminals and that he shot Neville. Mark realizes that Jimmy knows Neville. In the background, Mandy re-enters the room, Screaming that they shouldn’t talk about that stuff here. Mark then tells Jimmy that he heard about the contracts and that Jimmy was meant to do them, he then proceeds to put a gun up to Jimmy’s head, begging him not to shoot him while his kids are here, Mandy reinforces that Jimmy looks up to Mark and that he would never kill him. After he apologizes and gives money to Jimmy, Mark leaves the apartment. Jimmy then calls up Neville, informing him that Mark is going to the Bojangles Club and that they’ll meet him there.

After a brief phone call, Mark then runs into Sammy the Turk again. After a few drinks, Sammy and Mark go into a parking lot outside of Bojangles, Mark then produces a Sawed-off 410 Shotgun and questions Sammy on why they’re there. After a brief argument, Mark shoots him in the eye, Sammy begins to walk away and collapses. Mandy had witnessed the murder and tells Jimmy of it. The pair then leave. Later, Mark meets with Downie and Cooney, explaining the shooting of Sammy, changing the story but ultimately admitting to killing him, after Sammy supposedly took his handgun. Downie and Cooney soon affirm Mark that he isn’t the one that killed Sammy and that they believe Mark to be a liar, stating that they’ve picked up the man who committed the murder. Mark then later visits his father, admitting that he killed the man at Bojangles to which Keith replies; “that’s my boy, one in the skull!”

Mandy Carrol turns Crown Witness against Mark for the murder of Sammy the Turk. It’s then revealed that Sammy took Mark out to the car park for Jimmy to cash in on the Contract against Mark, but unknowingly took him to the wrong car park. Mark then beats the murder charge but is convicted of Malicious Wounding of Neville Bartos, and is sentenced to 5 years. The scene then turns to the interview that is viewed during the beginning of the film but during the filming stage inside the prison.

The scene then turns to the present day, with Mark and the two Correctional Officers watching the interview on TV in Mark’s cell. After the interview, Mark has a brief conversation with the Officers and they leave the cell. After the door closes, Mark brushes off his trousers, before staring aimlessly at the wall of his Prison cell.