Underbelly

The Carlton Crew crime syndicate is introduced: Mick Gatto, Mario Condello, Alphonse Gangitano, Graham Kinniburgh and Lewis, Mark and Jason Moran. Gangitano kills a man at a party over a small debt, and using fear convinces key witnesses to flee the country. With Jason Moran's assistance, he then smashes up an inner city nightclub injuring thirteen innocent people.

Alphonse pleads guilty in his assault case, but his associates intimidate the witnesses, frustrating the police trying to convict Jason. Alphonse tries to redeem himself and decides to leave the criminal world, but is murdered by Jason over a stripper they both were having an affair with.

The Moran brothers buy a pill press from a bikie gang. Jason's driver Carl Williams secretly begins making his own supply and forms an alliance with Moran rival Tony Mokbel. When one of the bikies kills two people, his ex-wife Tracey Seymour, a former girlfriend of both Jason Moran and Alphonse Gangitano is convinced by Det. James to testify against him, only to be murdered as a result.

Carl's cheap drugs throw the city's trade into chaos. Drug dealer Dino Dibra's plan to extort money from the Morans and their rival Nik Radev goes wrong when he kidnaps a junkie no one wants to pay the ransom for. When Carl is busted, the Morans discover the double-cross and Jason shoots him in the stomach. Meanwhile, Detective Owen convince a foreign national to testify in Jason's assault case.

With Jason in prison, Mark Moran takes over the family business, turning Tony Mokbel in to a corrupt officer from the drug squad. Carl asks Dino Dibra to kill Mark, but Dibra refuses and instead teaches him how to do the job himself with assistance from another thug, the rapist Mr. L. As Jason stews in jail, Carl kills Mark outside his home and, with Mr. L's help, establishes a perfect alibi.

Mark and Jason's father Lewis hires Mick Gatto's associate Andrew "Benji" Veniamin to avenge his stepson, believing the killer to be Dibra. As Dibra is a close friend, Benji hesitates until Dino incriminates himself. However, after Tony Mokbel is viciously beaten in a confrontation Gatto does nothing to prevent, Benji offers his services to Carl.

Carl is jailed for drug offenses, leaving his wife Roberta to run the business. Roberta is furious when rival dealer Paul Kallipolitis successfully extorts money from her. Kallipolitis makes the mistake of betraying his old friend Benji, who murders him.

Under financial pressure caused by the Williams' trade, Carlton Crew loanshark Mario Condello begins calling in his debts. Jason Moran is given special parole conditions to allow him to move to London and be safe from harm. Through a listening device in the Williams' home, Det. James discovers Benji's identity as he and Roberta begin an affair.

Jason Moran returns from London. Concerned for his safety, his father Lewis offers to take over the day to day running of the business but is arrested during a bust. With Benji under police observation, Carl offers the contract to Mr. L and Mr. T. In a city park in front of his children, Jason and his minder are executed.

Carl orders a hit on Willie Thompson, unaware he was a friend of Tony Mokbel. Ignorant of the perpetrator, Tony blames another small time dealer Michael Marshall and asks Carl to take care of it. Carl's hitmen Mr. L and Mr. T shoot Marshall in the street while under police surveillance and are immediately arrested.

Carl publicly accuses Detective Owen of corruption. Graham Kinniburgh and Mick Gatto fear for each other's safety. When Kinniburgh is murdered, Gatto suspects Benji. Carl agrees to end the violence but calls Benji's loyalty into question. Gatto calls Benji to a meeting and kills him, where he is subsequently arrested.

Consumed by a desire for vengeance over Benji's death, former Carlton Crew lackey Lewis Caine pushes Carl to take out a contract on Mario Condello. Meanwhile, Lewis Moran is gunned down in a crowded bar. As Caine moves on Condello, his double-crossing accomplices murder him.

As Carl makes plans to have Condello killed, Detectives Owen and James convince his jailed associates Mr. L and Mr. T to testify against him, finally getting the evidence they need to arrest him and bringing the war to an end. In the epilogue, it is revealed that Carl and Roberta divorce while Mick Gatto is cleared of any wrong doing and is released from prison.