Prince Albert Victor, Duke of Clarence, often recognized as Prince Eddy, finds himself entangled in a forbidden romance with Annie Crook, a humble shopgirl from the gritty streets of London's East End. What Annie does not realize is that Prince Eddy is visiting her under the guise of an alias, and their secretive affair leads to the birth of a child. Tragically, this romance catches the eye of Queen Victoria, who orders the separation of Prince Albert Victor from Annie. In a cruel twist of fate, Annie is institutionalized following the Queen's instructions to Sir William Gull, her royal physician, who is commanded to undermine Annie's mental well-being by interfering with her thyroid gland.
As events unfold, the couple's daughter is placed with Annie's parents, facilitated by Walter Sickert, an artist and confidant of Prince Eddy, who had accompanied him during his visits to Annie. Misguidedly believing that the child is the product of a scandalous union with his daughter, Annie's father becomes engulfed in shame. Reluctantly, Sickert gives the child to Annie's family, unaware of the brewing turmoil.
The scandal begins to bubble over when Annie's acquaintances—a group of prostitutes including Mary Kelly, Polly Nichols, Anne Chapman, and Liz Stride—who are aware of the royal ties of the illegitimate child, concoct a plot to blackmail Sickert. Upon discovering their scheme, Queen Victoria takes drastic measures by commanding Gull to silence them. The police, already informed of Gull's intentions, are instructed to remain idle until he executes his grim plan.
As a significant Freemason, Gull recruits John Netley, a carriage driver, to aid in a series of murders in Whitechapel. He rationalizes these heinous acts as necessary warnings against an imaginary Illuminati threat to the monarchy, believing they form part of a dark ritual meant to preserve male dominance. Amidst his murderous spree, Gull targets Mary Kelly but inadvertently also claims the life of Catherine Eddowes, who had been using Kelly’s name as an alias. As the body count rises, Gull begins to lose his grip on reality, experiencing a harrowing vision while killing a woman he mistakes for Kelly.
Gull leads Netley on a disturbing tour of London's historical sites, sharing what he sees as their hidden mystical importance. In a chilling moment, Gull compels Netley to compose the infamous From Hell letter. In the aftermath, various figures begin to claim responsibility for the horrors inflicted upon Whitechapel through letters sent to the police, solidifying the notoriety of the name "Jack the Ripper."
As Inspector Frederick Abberline delves deeper into the gruesome mystery of the Ripper murders, he finds himself outsmarted by an elusive killer. It is here that Robert James Lees, a magnetic spiritual advisor to Queen Victoria, steps in with a revealing insight, implicating Gull as the mastermind behind the chaos. Meeting at a critical juncture, Abberline and Lees confront Gull, who confesses to his horrifying deeds. However, their findings are quickly dismissed by the higher-ups of Scotland Yard, who claim Gull acted alone, driven merely by insanity. Undeterred, Abberline unravels a sinister motive: Gull's intent to unmask the royal scandal involving the Duke of Clarence's illicit offspring. Infuriated by the ensuing cover-up, Abberline resigns from the Metropolitan Police and considers leaving England to join the Pinkertons.
Simultaneously, Gull is summoned before a clandestine Masonic council, where he is deemed insane and subjected to a mock funeral. Under the alias "Thomas Mason," he is imprisoned, while the Freemasons go so far as to frame Montague Druitt, a schoolteacher, for the Ripper crimes, ultimately leading to his death, staged as suicide. Years later, Gull's spirit embarks on a chilling odyssey, observing the brutality of the London Monster while seemingly influencing a line of serial killers throughout history, from Peter Sutcliffe to Ian Brady. His spectral journey even touches Netley, whose fate is irrevocably bound to Gull's dark legacy. Notably, Gull's mystical experiences appear to inspire both Robert Louis Stevenson’s Strange Case of Dr Jekyll and Mr Hyde and William Blake's haunting artwork The Ghost of a Flea. In his final moments of consciousness before departing this life, Gull's spirit encounters an Irish woman with four children named in honor of the Ripper's victims, only for her to scorn him, commanding him to "return back to Hell."
