Watch Underbelly Season 4 in Australia

The true story of glamorous crime queens Tilly Devine and Kate Leigh, and their deadly battle to control Sydney's underworld in the 1920s.

The true story of glamorous crime queens Tilly Devine and Kate Leigh, and their deadly battle to control Sydney's underworld in the 1920s.

Norman Bruhn's Razor Gang pushes the underworld to crisis point, threatening the crime empires of Kate, Tilly and Phil Jeffs. Amid public outrage, the police fight a losing battle to stop rival Razor Gangs terrorising the streets. The rival underworld bosses convene a summit to deal with Bruhn's gang, but are betrayed when Tilly takes matters into her own hands. After being rejected by Nellie and taunted by his rivals, Frank 'The Little Gunman' Green finally gets his chance to shine.

Furious over Tilly's decision to kill Norman Bruhn, Kate sparks an all-out war by recruiting Tilly's prostitutes to sell cocaine. Snowy Cutmore returns to Melbourne for a fateful showdown with crime boss Squizzy Taylor. Fresh from his first kill, Frank 'The Little Gunman' Green wins the ultimate prize — Nellie Cameron. But can he keep her?

Phil Jeffs faces the hangman's noose for a scandalous crime that has all of Razorhurst guessing.

The rivalry between Kate Leigh and Phil Jeffs reaches boiling point, leading to a legendary street battle between their rival gangs. Jeffs is determined to put Kate and Tilly out of business by poisoning their cocaine supply and slashing their workers. The police create Australia's first drug squad to fight the deadly cocaine epidemic, and Kate starts an affair with a sexy young gangster, angering her faithful lieutenant Wally.

With Kate Leigh in prison, Tilly devises a radical new strategy for taking control of Razorhurst. Meanwhile, Wally faces an uphill battle to protect Kate's business and family interests while she is in prison. A dashing nightclub singer pledges his undying love to Nellie Cameron, with tragic results. And Black Aggie is publicly humiliated in a bar-room brawl with Nellie but finds love from an unlikely source.

Black Aggie strikes up a romance with Greg “the Gunman” Gaffney and gives-up prostitution. But she’s still dirty on Nellie for putting her out of work, so she fronts her with a cut-throat razor. Frank Green intervenes and gives Aggie thrice as many cuts and bruises than she started out with.

Fresh out of prison, Kate Leigh puts a bounty on the heads of Tilly's husband, Big Jim Devine, and her chief henchman, Frank Green, as payback for the murder of Greg Gaffney and the razor attack on Bruce Higgs. In a pre-emptive reprisal Tilly vows to eliminate Kate's muscle before they eliminate hers. Meanwhile, Kate learns the truth about her son-in-law and is forced to take action that will drive her own daughter away.

Wally becomes an outcast when he gives evidence against Tilly's gunman. Big Jim is desperate to hide his cowardice from the rest of Razorhurst, while Kate shoots to kill when she is the victim of a home invasion.

Tillys decision to visit London has dire consequences for her business and marriage. With Tilly in London, Kate moves to seize control of the drug trade. Fresh from prison, Guido is determined to become the Al Capone of Australia; and the police suspect they have a traitor in their ranks.

Big Jim faces the noose over the attempted murder of his wife but at the 11th hour Tilly refuses to testify against her husband and the charges are dropped. The ultra-nationalist New Guard are proving such a danger to his government that Premier Jack Lang guarantees Bill Mackay the new title of NSW Police Commissioner if he can stamp them out. His wife having left him and taken the kids, Frank throws in his lot with Nellie and the pair try to escape Razorhurst for a new life in Queensland. Guido Calletti's ambitious plans to seize Kate's cocaine supply are forgotten when he and Frank clash over Nellie yet again.

After a decade of gang warfare, Kate and Tilly have their final showdown. Phil Jeffs returns from exile and vows to drive Kate Leigh out of business. Frank and Guido fight to the death over the love of Nellie Cameron, and Razorhurst celebrates the grand opening of the Sydney Harbour Bridge.