Nellie is the formidable, famous "Queen of Clubs" in 1926 London. A mother of six, she built a massive, highly lucrative, and largely illegal nightclub empire from nothing. Resourceful and sharp, she constantly monitors the myriad threats to her business, from ambitious police officers to mysterious figures from her past. She is frequently disturbed by the ghostly apparition of a former employee named Maud.

Frobisher is a detective stationed at the Bow Street police station who acts as a moral counterpoint to London's corrupt underworld. He is a mundane, law-abiding man who drives an "Everyman" car and stubbornly wishes to sweep crime from the streets. Frustrated by the rampant vice in the city's nightclubs, he orchestrates plans to infiltrate Nellie's empire.

Gwendolen is a former World War I nurse who travels to London searching for two runaway girls. Independent and hardened by her wartime experiences, she is financially secure due to a family inheritance. Her search leads her to ally with Inspector Frobisher, who recruits her to go undercover into the dazzling but dangerous nightclub scene.

Freda is an ambitious runaway who flees an abusive home life in pursuit of stardom on the West End stage. Innocent but fiercely determined, she navigates the dangerous, seedy underbelly of London's entertainment world. Her grand dreams often blind her to the immediate threats surrounding her in the city.

Maddox is a corrupt Detective Sergeant in London who has long taken bribes from Nellie Coker to protect her clubs from police raids. He is increasingly ambitious and greedy, harboring desires to move beyond mere payouts and violently seize control of the nightclub empire for himself.

Oakes is a police sergeant working alongside Frobisher and Maddox. Though he maintains a jovial exterior, he operates in the corrupt shadows of London's police force. He actively participates in illicit schemes targeting vulnerable young women in the city.

Azzopardi is a mysterious man and former jewel thief with unfinished business in London. He tracks down the Coker family seeking "compensation" and attempts to force Nellie into selling her clubs for a fraction of their worth. He aggressively exploits any weakness in the Coker family to achieve his goals.

Niven is Nellie's eldest son and a veteran of World War I. Unlike his siblings, he does not directly manage the family nightclubs, instead running his own enigmatic businesses. He possesses a strong sense of familial loyalty, keeping a watchful eye on the various threats circling his mother.

Edith is Nellie's highly capable right-hand woman. She is responsible for overseeing the bookkeeping and accounting for the family's extensive nightclub empire, specifically managing the flagship Amethyst club. She holds closely guarded secrets that could compromise the family business.

Ramsay is Nellie's son who manages the Sphinx club, though mostly as a figurehead. He was too young to fight in the war and struggles with feelings of inadequacy. He nurses an addiction to cocaine and desperately wishes to achieve independent fame by writing a brilliant crime novel.

Florence is a runaway from a well-to-do, religious family. Accompanying Freda to London, Florence is more interested in reading thrillers and seeing the sights than pursuing stardom. She possesses a strong moral compass and often worries about the consequences of their actions in the dangerous city.

Betty is one of Nellie's daughters, responsible for overseeing the Pixie club. Nellie harbors ambitions for her to marry into the aristocracy to elevate the family's social standing.

Shirley is one of Nellie's daughters, who helps manage the Foxhole club. Like Betty, she is expected by her mother to secure a titled husband.

Kitty is Nellie's youngest daughter. Too young to manage the clubs, she spends her time daydreaming and avidly reading the gossip papers about London's elite.

Lottie is Inspector Frobisher's French wife. Hidden away from his colleagues, she suffers from severe mental illness and a morphine addiction, trapping both herself and her husband in a joyless marriage.

Vivian is a prominent gossip columnist who reports on the escapades of the "Bright Young Things." He is writing a novel and frequently interacts with London's elite socialites.

Mrs. Darling is the landlady of the boarding house on Henrietta Street where Freda and Florence initially stay upon arriving in London.

Maud is a former dancing girl at one of Nellie's early clubs who died of an opium overdose. Her body was dumped in the Thames, and her ghostly apparition frequently visits Nellie as an omen of reckoning.

Norman is a young newspaper boy who observes the bustling crowds of London, offering a working-class perspective on the city's wealthy elites.

Minnie is a tragic figure found dead in the Thames wearing only a silver shoe and a locket. She symbolizes the many lost girls consumed by London's dark underbelly.

Gerrit is the bartender at the Sphinx club who functionally manages the establishment in place of Ramsay Coker. He also supplies Ramsay with illicit drugs.