In the shadowy streets of London's Soho, an array of characters navigate their unsavory trades. Thieves, beggars, and harlots mingle amid an atmosphere thick with the threat of crime. As a balladeer narrates the rise of lawlessness, the notorious figure at the center—Captain James MacHeath, or "Mack the Knife"—makes his presence known, sending ripples of fear through the community.

The Peachums and Their Schemes

Within this murky world, Jonathan Jeremiah Peachum runs a beggars' organization, exploiting the generosity of the wealthier class. Filch, a novice hoping to join the ranks, begrudgingly pays Peachum for protection and a costume, which Mrs. Celia Peachum skillfully ages for authenticity. Meanwhile, their daughter Polly becomes entangled with a mysterious suitor, whom Celia eventually identifies as Mack the Knife. Concerned, Peachum is momentarily calmed by Celia, and together they sing of the fleeting enchantment of youthful romance.

A Wedding in Unlikely Surroundings

In an empty stable, Mack and Polly celebrate their wedding, albeit in unconventional style. Mack's henchmen, dressed for the occasion, have furnished the venue by pilfering furniture and provisions for the feast, though their selections are far from tasteful. Their choice of a dirge for a wedding hymn adds to the comedic tone. The ceremony proceeds, and Polly captivates the guests with a song about the underdog's revenge against the elite. Mack's friend, Tiger Brown, who also happens to be the police chief, arrives to assure Mack of his clean slate. The two reminisce, singing about their camaraderie from army days.

Polly's Dilemma

Polly justifies her nuptials to Mack to her parents, suggesting that societal norms do not always equate to personal happiness. Although her father is irate, the clamor of beggars interrupts, prompting him to hatch a plan to turn Mack's consorts against him. Polly, proud of Mack's connection with Tiger, faces her parents' cynical worldview as they lament human greed and malevolence through song.

Mack's Flight from Arrest

Alerted by Polly about the impending danger, Mack prepares to flee, instructing her to handle the business in his absence, including collecting his share from his gang and delivering them to the authorities. She consents, and the gang pledges their loyalty to her. Despite the assurances, Polly laments their separation through a poignant song.

Betrayals and Escapes

Celia entices Ginny Jenny to betray Mack, forming a plot while entertaining themselves with "The Ballad of Sexual Submissiveness." When Mack seeks refuge in Jenny's brothel, their shared past resurfaces in song, but the anticipated police raid forces Mack to flee, only to find Celia and more officers ready to capture him.

Prison Intrigues

Once imprisoned, Mack rebuffs Tiger's apologies for his arrest. Alone, he tries to bribe his way to freedom, fantasizing about a life of luxury. His complex relationships ensnare him further when Lucy Brown, Tiger's daughter, reveals her pregnancy. Polly's unexpected visit prompts Mack to feign disdain to protect Lucy's secret, leading to a sharp exchange between the two women in "The Jealousy Duet." With Celia's intervention, Polly is taken away, yet Mack succeeds in convincing Lucy to aid his escape. Peachum, ever resourceful, blackmails Tiger into recapturing Mack, while Mack and Jenny sing about the parasitic nature of humanity.

Final Acts and Redemption

As Peachum's beggars prepare for Queen Victoria's coronation, Jenny demands her due reward from Celia, who withholds it until Mack is back in custody. A confrontation ensues as Tiger attempts an arrest, but Peachum's cunning redirects him to Sulky Tawdry's hideout. Amidst this chaos, Peachum muses on the futility of life, mirrored by Jenny's reflections on its absurdity. In a turn of events, Polly and Lucy reconcile, with Lucy...