John Standing, a recently dismissed teacher, crosses paths with his doppelgänger, Johnny Spence, a confident but troubled businessman, after they meet in a hotel lobby. Spence needles him toward a night of letting go, and the alcohol loosens both his guard and his sense of who he is. The next morning, Standing awakens disoriented, without his clothes or wallet, and Spence has vanished. He is collected by George, the chauffeur who services the Spence family, and struggles to explain the impossible turn of events. Taken to the sprawling family home, Standing is quickly pulled into a maze of loyalties, ambitions, and secrets—the sort of place where appearances must be kept polished even as the ground beneath shifting feet.
The Spence clan casts a long shadow over the glass business they run together, a venture that is steadily slipping toward collapse. Standing, who has not earned his place in this world, feigns a binding contract with a major customer to delay the inevitable. He begins to understand the different faces within the family: Spence’s younger brother Paul, who is capable yet lacking in confidence, and Spence’s sister Blanche, who harbors a fierce resentment toward Johnny for a friend’s suicide. The household is also populated by Spence’s wife Frances, his mother, and a pair of women who orbit the family’s fortunes—Nina, the sister-in-law, and Bela, a French artist who lives nearby. The only lifeline to saving the business appears to be Frances’s trust fund, but it comes with a chilling caveat: it can be paid out only if Frances bears a male heir or if she dies first. As Standing watches these pressures mount, he becomes entangled in a dangerous play of deceit where each party’s motive seems to shift with the next conversation.
When Spence returns to the house to recover his gun, he discovers Standing in a compromised moment with Frances. Rather than confronting him openly, Spence exploits the fragile bond between them, using the altered dynamic to press his own advantage and to test Standing’s loyalty. Meanwhile, Standing’s presence has already unsettled the family’s fragile balance, and the simmering tension begins to tilt toward a more perilous resolution.
During a shooting party lunch with the family, Spence engineers a devastating plan: he persuades Frances to take an overdose of morphine so that he can lay claim to the trust fund and rescue the ailing business. Frances, choosing the welfare of her kin over her own life, submits to the scheme, and her daughter Piglet bears witness to the troubling drama, misinterpreting Standing as the source of the danger. Standing hurries back to the house and finds Frances in a perilous state; with the aid of Charlotte, the carer for Spence’s mother, he manages to revive her and restore a fragile thread of life.
Confrontation follows confrontation as Standing ultimately faces Spence in the glass foundry where the business’s fate has long been hung in the balance. Spence offers Standing a share of the money if he agrees to play along, but Standing refuses. In a tense struggle, Spence forces Standing to switch clothing with him, intending to kill him and dispose of the body among the factory’s machinery. The encounter ends with Spence dead, the victim of a struggle that leaves Standing with the risk of exposure and damnation looming over him.
Returning to the house, Standing finds himself at a crossroads. Charlotte’s eyes have seen through the deception, and she persuades him to stay rather than vanish into the night. In the final moment, Standing is seen among the Spence family, Frances now pregnant, as they watch the Coronation on a newly acquired television set. The scene closes on a complex note: a man who walked in as a substitute for another must now decide how to live with the consequences of his impersonation and the fragile bonds that have held this tumultuous world together.
The film probes questions of identity, loyalty, and the cost of ambition, painting a portrait of a man who slips into another’s life not to belong, but to survive, only to discover that survival may require paying an even higher price than he anticipated.
