"Mirror Image" is an episode of the television series The Twilight Zone.
Millicent Barnes, age twenty-five, young woman waiting for a bus on a rainy November night. Not a very imaginative type is Miss Barnes, not given to undue anxiety or fears, or for that matter even the most temporal flights of fancy. Like most young career women, she has a generic classification as a, quote, girl with a head on her shoulders, end of quote. All of which is mentioned now because in just a moment the head on Miss Barnes's shoulders will be put to a test. Circumstances will assault her sense of reality and a chain of nightmares will put her sanity on a block. Millicent Barnes, who in one minute will wonder if she's going mad.
While speaking with the station attendant, she notices a bag just like hers in the luggage pile behind her. She mentions this to the ticket counter man, who says it's her bag. She doesn't believe this until she notices her bag is not beside the bench anymore. Later she goes to the bathroom to wash her hands and another woman there insists this is her second time there. Again, Millicent denies this. Upon leaving the bathroom, she glances in the washroom mirror and sees herself, sitting on the bench outside.
Still later, she meets a man, Paul Grinstead, who is waiting for the same bus. They talk about the phenomenon. Paul, attempting to calm Millicent, says it is either a joke or a misunderstanding caused by a look-alike. Just then the bus arrives and the two prepare to board it, but just as they start to, Millicent looks in the window and sees the copy of herself, seated already upon the bus. She runs back into the stop, driven almost into hysterics while her identical counterpart has a facial expression of malicious indifference and something of enjoyment.
Paul follows her in and agrees to wait for the 7:30 bus. While they wait, Millicent, lying on the bench wrapped in a blanket, insists the strange events are caused by an evil double from a parallel world; a nearby, yet distant alternate plane of existence that comes into convergence with this world by powerful forces, or unnatural, unknown events. When this happens, the malevolent impostors enter this realm. Millicent's doppelgänger, evil in nature, can survive in this world only by eliminating and replacing its good counterpart - Millicent herself. The real Millicent is seemingly correct in her postulations, but no one will believe her.
Paul says the explanation is "a little metaphysical" for him, and believes that Millicent's sanity is beginning to unravel. Paul tells Millicent he'll call a friend in Tully who has a car and may be able to drive them to Syracuse, but, in reality, he calls the police. After Millicent is taken away, in an overly direct and presumptive style by two New York policemen, Paul begins to settle himself. After drinking from a water fountain, Paul notices that his valise is missing. Looking up towards the main doors, Paul notices another man running through them and away from the bus station. Pursuing this individual down the street, Paul discovers, to his absolute horror, that he is chasing his own copy, its face a mask of excited, evil delight.
As his evil copy runs away and vanishes, Paul now begins his own horrific descent into a hellish mixture of madness, terror, and future uncertainty that he cannot explain to others, lest he be considered as insane as he and others thought Millicent Barnes to be.
Obscure metaphysical explanation to cover a phenomenon, reasons dredged out of the shadows to explain away that which cannot be explained. Call it parallel planes or just insanity. Whatever it is, you find it in the Twilight Zone.
Next week on The Twilight Zone, we put you on a front porch. Summer evening, tree-lined street, typical small town, and then we pull the rug out from under your feet...and we throw a nightmare at you. Claude Akins, Jack Weston, and Barry Atwater are your neigbors just at that moment when "The Monsters Are Due on Maple Street." Don't chicken out. See you next week.