An escaped criminal, known as Harry Crowl, Charles Middleton who prefers to be called by his prison number 39013 (pronounced Thirty Nine - Oh - Thirteen), returns to exact vengeance on the man who sent him away: Horace Granville, a wealthy philanthropist who provided Crowl’s sentence. Crowl abducts Granville and traps him inside his own house, disguising himself as the frail old man and living behind a glass barrier that only his doctor may cross. From this uneasy perch, he methodically starts to dismantle everything Granville owns, turning private space into a stage for menace and control.
Already the target of a calculating assault, Granville’s world expands into danger as Crowl sets his sights on the Granville Amusement Centre, where a troupe of acrobats performs. The trio—Gene Townley, Charles Quigley; Bert Knowles, David Sharpe; and Tiny Dawson, Bruce Bennett—make a daring escape from the flames, only to see Gene’s younger brother sustain severe injuries, eventually dying from the wounds. This tragedy steels the resolve of the performers, who decide to seek justice and take on cases as private investigators, believing they are working for the man who is truly Horace Granville. The shift from witnesses to sleuths marks the beginning of an uneasy alliance with the very name they fear.
As the daredevils pursue clues, a chilling thread runs through the story: a mysterious cloaked figure known only as “The Red Circle” offers help, while a web of deadly traps tightens around the Granville estate. The investigation leads them to a secret room within the Granville residence, where the real Granville is kept in a cell that mirrors the grim confinement that Contained the 39013 prisoner. The room is ingeniously rigged—the weight that keeps the secret door balanced also serves as a potential trigger for a lethal gas release if anything disturbs the setup. The unsettling mechanism underscores the peril that Granville faces and the chilling efficiency of his captor.
In one crucial reveal, the film uses the claustrophobic setting to pull the audience deeper into the mystery. The system is designed so that, should the scale tilt or weight drop, dripping reservoirs will dry up and gas capsules will rupture, bringing swift, deadly consequences to the confined man who is supposed to be under guard. This tension culminates in a stark, iconic line that caps the scene: > You best hope I continue to live, Granville.
What unfolds is a serial-driven narrative that blends suspense with action and puzzle-like plotting. Each chapter peels back another layer of the conspiracy, while the Red Circle’s identity—and its true motives—remain a tantalizing question mark. The story’s core rests on the chemistry between the resourceful trio of acrobats who pivot from victims of arson to investigators of a larger scheme, and on the chilling claustrophobia of a hidden prison built to imprison a man inside his own home. The tone remains measured and clear, even as danger multiplies and the truth crawls from the shadows into the light.
- Key players return not as mere victims but as agents shaping the investigation: Miles Mander stars as Horace Granville, a man of wealth and philanthropy who becomes the central figure in a plot that tests loyalty, courage, and nerve.
- The action is propelled by tight, methodical set pieces and danger-laden sequences that keep the stakes high, even as the mystery broadens beyond a single vendetta.
- The Red Circle’s presence adds a hush of mystique, guiding the daredevils toward discoveries that could topple Crowl’s elaborate trap and free the real Granville from his glass-walled prison.
In the end, the film crafts a sprawling, early-serial mystery where vengeance, ingenuity, and a cloak-and-dagger alliance collide within a carefully guarded estate. The danger is never far, the traps are meticulously designed, and every revelation pushes the trio closer to the truth, even as they wrestle with the very real threat posed by a man who believes his life depends on Granville’s continued existence. The result is a tense, immersive journey that stays true to its premise while expanding the tension through character-driven investigation, perilous dares, and the ever-present shadow of The Red Circle.
