Centuries ago, Dirk Van Prinn is rumored to be a sorcerer and worse. At his isolated home, Van Prinn is working on a formula for a special form of glass when his when his landlady, Mrs. Ames, knocks on the door and tells him that the silversmith has left a package for him. Van Prinn tells her to leave it outside the door and go, and then goes to the door to get the package. Mrs. Ames tries to get a glimpse inside but he sends her away.
Once he’s alone, Van Prinn lights his room and sits down before a mirror. He picks up the glasses he has crafted from the special glass, closes his eyes, and puts them on. After a moment he opens his eyes and stares at his reflection in horror.
In the present day, junkman Joe Henshaw is at home having breakfast as his wife Maggie berates him for bidding $100 on a blind lot from the city. Joe’s worker, Charlie, comes in with the mail and Joe discovers that he can barely read it. Maggie tells him to give in and get some glasses, but Joe insists that he can see what he needs to. Maggie can’t help telling Charlie that Joe wasted their money on a blind lot from the old Bleeker house. Once Charlie leaves, Joe explains that he got a tip from a friend at City Hall that there was some old furniture in the attic. He insists that sometimes they have to take a chance, and wonder why she’s been treating him like dirt since he hired Charlie. Maggie refuses to discuss it and Joe says they’ll settle it later.
Joe and Charlie drive to the Bleeker house and look around. They find a locked door and break it down, and find a collection of old books. The books fall apart at the touch and Charlie warns that Maggie won’t be happy. Joe orders him out and then kicks a desk in frustration. A hidden panel opens, revealing a pair of yellow-gold lensed glasses, “cheaters.” Joe puts them on and discovers that his eyesight is vastly improved.
That night, Joe comes home and finds Maggie setting the table. She wishes him happy birthday and admits that she forgot it a week ago. Maggie apologizes for how she acted, much to his surprise, and he admits he hasn’t been easy to live with either. As she goes to wash up, Joe puts on the cheaters to read the mail and notices that one letter from the morning is missing. Maggie claims it was a bill from the gas company. As Joe looks at her, her face glows and he hears her thinking that she’s fleecing him. When he lifts the cheaters, he sees her normally and Maggie claims that she’s happy for him. When he lowers them back down, he hears her thinking that he’ll be dead in the morning. Realizing something is going on, Joe asks her about the gas bill and hears her thinking that someone wants to buy the property.
Charlie comes in with a jug of wine. Joe hears him thinking that it’s poison and he plans to kill him. Maggie and Charlie laugh and insist on Joe having one glass of wine. Charlie pours it out while Joe hears them thinking that once they get him drunk, they’ll take it him to the Bleeker house and arrange an accident. As Charlie continues to pour drinks, Joe hears them declaring their love for each other. Joe takes off the cheaters and asks Charlie what the word “Veritas” means that is inscribed on the cheaters. Charlie explains that it’s the Latin word for “truth.”
Joe goes to the garage, claiming that he wants to move the truck inside. He bangs the door and then sneaks back and hears Maggie asking Charlie if he’s lost his nerve. They kiss and Joe grabs a crowbar and goes back. He beats Charlie to death and then attacks the screaming Maggie. A passing policeman hears the screams and comes inside to find Joe standing over the two bodies. When he asks why, Joe points at the glasses behind the cop and yells “cheaters!” He tries to smash them and the cop assumes that he’s attacking him, and shoots him down. With his dying breath, Joe tries to grab the cheaters but fails.
Later, a bed-ridden old lady, Miriam Olcott, calls her friend Clarence and insists that her nephew Edward and his wife Olive are trying to poison her. She pours the tea into the flowerpots while admitting that they’ve come to help her since her husband’s death, but they’re keeping her prisoner while they hold parties. When she hears Olive coming, Miriam quickly hangs up. Olive makes sure that Miriam is comfortable and leaves. Once she’s gone, Miriam dresses and goes outside. She finds her way to a woman’s store and asks for bright yellow cloth. When the salesgirl’s back is turned, Miriam steals some of the cloth.
Miriam leaves and sees a man named Burgin packing up the inventory. Burgin explains that he bought up the inventory after Joe killed his wife and her boyfriend. Miriam notices the cheaters and pays two bits for them. When she returns home, Edward and Olive ask where she’s been. Miriam lies and says that she was fitted for glasses, and then puts on the cheaters. When she dons them, she hears Edward thinking that she’s dressed for Halloween, and then Olive thinking that Miriam has stolen again and Edward will have to take everything back. Frightened, Miriam starts to go up the stairs. Olive tells her that Clarence is coming and will bring up her tray while they leave. Miriam hears Edward thinking that she’ll dead after that night.
As Miriam examines the cheaters, Clarence arrives with her tray. She tells him that Edward and Olive plan to kill her. He ignores her and she dons the cheaters, only to hear him thinking that he plans to shove her down the stairs. Miriam asks who inherits if she dies, and Clarence tells her that Edward and Olive do as long as they care for him. Meanwhile, he thinks that he’ll receive half of the inheritance if he arranges an “accident” for her. Clarence goes to get her a drink and Miriam takes out a hatpin. When Clarence offers her a drink, she stabs him in the heart with the needle and smiles in satisfaction. She drops the cheaters on a chair and offers Clarence a toast to the truth, and then pours herself another drink. She continues to drink until she passes out, dropping the glass near the fireplace. The flames spread, setting her nightgown on fire.
A year later, Edward and Olive prepare for a costume party that they’re hosting. Edward assures her that their host, Torgenson, will be his advocate into the town’s gentry. He’s invited Sebastian Grimm, a writer, and his wife, in the hopes that Sebastian will start a game of poker and give Edward the opportunity to lose gracefully and impress Torgenson.
Edward dresses as Benjamin Franklin and attends the party. Sebastian points out that he’s not wearing Franklin’s traditional glasses, and then suggests they play poker. Edward cheerfully loses, much to Sebastian’s disdain. Olive comes in with drinks and gives Edward the cheaters that she found among Miriam’s belongings. As they start again, Edward hears another player, Judge Pfluger, think of him as a fool and a poseur. Sebastian takes the cheaters and notices that the word “Veritas” is inscribed upon them. Edward takes them back and puts them on, and hears the players thinking what cards they have. He realizes that Torgenson is cheating and knows that Edward is losing to impress him. Edward accuses Torgenson of cheating and refuses to back down. He tells Torgenson to raise his arm, but is surprised to discover that there are no cards there. He spots them on the floor and shows them to Sebastian and Pfluger. However, Torgenson claims that Edward hid them on the floor to try and embarrass him. Edward is forced to admit that he didn’t see him hide the cards, and explains that the cheaters told him. The others believe Torgenson, and Edward grabs him and flies into a frenzy. Sebastian is forced to hit him with a candlestick and inadvertently kills him. He picks up the cheaters and pockets them.
Later, Sebastian shows the cheaters to his wife, Ellen, and suggests that they have some kind of power. He shows Ellen a rough draft of his new book and explains that he plans to incorporate the cheaters into the last chapter of his book. Sebastian has documented the five deaths and believes that the cheaters were ultimately responsible for each one. Ellen doesn’t believe it, but Sebastian tells her that he’s traced them from scene to scene, and that the cheaters reveal the ultimate truth to the user. When his wife asks if he has donned them, Sebastian says that they were intended for the user to see one’s self, not read minds. He knows about Van Prinn and how he created the cheaters. Ellen tells him to put them away, and Sebastian jokingly threatens to wear them and see the truth about her. She backs away and Sebastian invites her to come along with him to the Bleeker house, which was built by Van Prinn, for the purposes of “atmosphere.”
The couple arrives at the Bleeker house and Ellen asks what happened to Van Prinn after he wore the cheaters. Sebastian admits that he came to the house that morning and then informs Ellen that Van Prinn hung himself. He starts to go upstairs, ignoring Ellen’s objections, and explains that Van Prinn made the glasses to find out if he was one of the great men of his generation.
Sebastian enters the upstairs study and goes to the mirror that Van Prinn used centuries ago to contemplate himself. As Sebastian dons the glasses, a wind springs up and closes the door, and mocking laughter echoes through the room. Sebastian turns to the mirror and sees himself. His reflection asks if he wants the truth about himself, and Sebastian says that the others couldn’t handle their own emotions. Sebastian’s reflection tells him to step closer. Sebastian stares and sees his own hideously distorted reflection. As Ellen bangs on the door, Sebastian claws his eyes out.