Sally Lockhart, Billie Piper, is six years removed from The Ruby in the Smoke and has carved out a reputation as a sharp, self-assured financial consultant in a bustling Victorian world. When a Miss Walsh, Antonia Pemberton, arrives at Sally’s office complaining that Sally’s financial advice cost her everything, the seeds of a dangerous investigation are planted. Sally’s life is quietly intertwined with those around her: her huge, loyal black dog Chaka, and Frederick Garland, Sally’s friend, whom JJ Feild plays as a figure torn between affection and restraint. Frederick’s feelings for Sally are clear, yet Sally remains unsure about marriage, even as Jim Taylor, Sally’s loyal ally and now a stagehand at a local theatre, lends a steady hand to the work that lies ahead.
The case quickly widens into a web of corporate intrigue centered on Anglo-Baltic and the shadowy North Star enterprise. At the heart of the mystery is Axel Bellmann, a ruthless player whose grip tightens as Sally digs into the collapse of Anglo-Baltic and the billion-dollar ambitions behind North Star. The threads pull Sally toward a grim nexus of finance, power, and deception, with Frederick Garland, JJ Feild, and Webster Garland, John Standing, running a photography shop that doubles as a private investigations office on Burton Street. The pair become crucial allies as Sally pieces together fragments of evidence and testimony that point toward a broader conspiracy than a mere business failure.
A charitable performance becomes the series of events’ pivot, as stage magician Alistair Mackinnon, Julian Rhind-Tutt, encounters danger that requires Frederick’s protection. Mackinnon’s escape from harm leads Sally, Frederick, and their associates to a whispered trail about the man pursuing Mackinnon—an unsettling clue that makes Sally suspect Bellmann’s fingerprints on the scheme. The uneasy alliance grows when Sally and Frederick attend a seance conducted by a medium, Mrs. Nellie Budd, Doña Croll. The eerie proceedings—tables jerking, objects flinging, and eerie prophecies—are captured in photographs, including images of Nellie’s arms and the wires that fake the supernatural show. Nellie Budd insists she’s a conduit for genuine visions, though Frederick challenges her claims and shares what the sensors reveal.
As Sally’s inquiries intensify, her world collides with romance and risk. Isabel Meredith, Lyndsey Marshal, confesses her own heartbreak—she loves Mackinnon but cannot have him—and Jim meets Lady Mary Wytham, a woman who becomes a catalyst in a dangerous triangle. Jim’s encounter with Lady Mary deepens Sally’s suspicions about the connections tying together Bellmann, Wytham, and North Star. In another thread, Bellmann’s man Windlesham tries to intimidate Sally, but she stands firm and refuses to back down. Meanwhile, Charles—a friend of Frederick’s—unravels a more personal layer of Bellmann’s scheme when he discovers that Lady Mary and Mackinnon are entangled in a way that Bellmann fears.
The plot thickens as Sally exposes a web of lies surrounding Nellie Budd’s past and the hidden truths behind North Star. The discovery that North Star plans a devastating new weapon—the Steam Gun—promises to alter the balance of power in dangerous ways, not only on the battlefield but also as a tool for controlling a populace. Frederick, determined to protect Nellie’s sister Jessie Saxon and uncover the truth, learns more about the true nature of Nellie’s life, and the revelation about Mackinnon’s ties to Nellie’s past intensifies the stakes. Isabel’s life is put in peril when her room is ransacked by Bellmann’s henchmen, and a fateful encounter leaves Sally and Frederick fighting for their survival as malevolent forces close in.
In a confrontation that blends private investigation with street-level daring, Sally, Frederick, and Jim retrieve stolen files from Bellmann’s house and push back against the criminal machinery. Mackinnon returns to Burton Street, and a pivotal confession emerges in an exchange where Sally reveals her love for Frederick in a quiet, intimate moment that carries immense consequences. The pair share a private, fragile bond: > Not a word - not a word. < The trio then faces a cataclysmic turn as Windlesham engineers a fire that consumes the building, costlier than anyone anticipates. Jim sustains a broken leg during the escape, and Isabel’s fate becomes a tragic casualty of the night’s violence, while Chaka the dog dies in the confusion.
As the smoke clears, Sally discovers that Bellmann’s true motive is power, and the Steam Gun’s cataclysmic potential must be stopped. Bellmann taunts Sally at the North Star headquarters, offering marriage and influence, but Sally refuses to surrender her independence. With Mackinnon’s help, she decides to use Bellmann’s own obsession against him, and she ultimately triggers the Steam Gun’s destruction in a decisive, devastating move that collapses North Star’s ambitions and leaves Bellmann dead in the rubble. Sally survives the ordeal, rescued by Jim and Mackinnon, and the truth about Bellmann’s schemes—his violent hunger for control and a future built on fear—surfaces in the aftermath.
In the wake of the catastrophe, Miss Walsh’s money is recovered and safely redirected into Garland & Lockhart, Sally’s own business venture, ensuring a future for both the investigative firm and the people who relied on it. Jim, bearing a legacy of his brave rescue, walks with a lifelong limp, while Nellie Budd recovers and returns north with her sister Jessie. Mackinnon and Lady Mary depart for America, leaving Sally to contemplate what comes next, and Charles unveils a hopeful new home for Garland & Lockhart—a large, sunlit property with an orchard, tinged by the sense that it may be haunted. The final note of the tale is hopeful: Sally reveals that she is pregnant with Frederick’s child, signaling a personal future shaped by the trials she has endured and the alliances she has forged along the way.
