At a gentleman's club, braggart Jamie Tennyson speaks incessantly about all of his business ventures while forcing himself on anyone and everyone. Club member Colonel Archie Taylor grows increasingly irritated with Tennyson and then calls in his attorney, George Alfred. Taylor notes that in 30 seconds Tennyson will try to get a loan, while Alfred notes that Taylor's plan is incredible. He admits that Taylor's wager is not criminal and Taylor gives a note to the manservant to deliver to Tennyson.
Tennyson receives the note and reads it, then says it's nonsense. He asks Taylor if it's a joke and the colonel asserts that he's serious, then asks Tennyson's permission to inform the other club members of his wager. Upon agreeing, Taylor explains that he's betting Tennyson $500,000 that he can't remain silent for one year. Tennyson will be placed in a room for observation during the entire time, furnished with anything he desires for food and diversion, but if he speaks he loses the wager. Taylor explains that he thoroughly disdains Tennyson and doesn't believe he'll make it throuigh a year, but in the meantime he'll have several months of blessed silence until Tennyson folds. Tennyson accepts the wager and confirms that he will be incarcerated in the game room in the basement, in a glass cell covered with microphones. The room can be prepared the next night and Tennyson asserts that he will be there. Before he goes, he insists on having the check certified and placed on deposit in his name. Taylor asserts that his credit and honor are well known and refuses. As Tennyson leaves, Alfred warns him that Taylor is deadly serious, but Tennyson simply notes that his wife has expensive tastes and he needs the money.
Tennyson begins his stay the next night as Taylor watches him. After nine weeks Tennyson maintains his health and appetite, while Taylor figures he could only have withstood six weeks. The weeks and months contionue to pass and Tennyson remains silent. Alfred meets with Taylor after four and a half months and wonder how long his client plans to continue with what he believes is a practical joke. Taylor believes Tennyson will soon snap, but Alfred wonders if he has the money. Taylor finds his comment insulting, but Alfred believes Tennyson will remain silent the entire year.
With three months left, Taylor confronts Tennyson and notes that he thinks the entire thing has gone too far and he offers the man $1,000 to leave. Tennyson turns down the offer but Taylor notes that Tennyson's wife is growing lonely and has been seen with other young men. She has never repsonded to Tennyson's notes to pay a visit and Taylor notes he may lose his wife if he doesn't leave. Over the next two months Taylor continues to torment Tennyson with facts about his wife but the man doesn't break or speak even when the colonel offers him $5,000, then $6,000.
One year later, the club members assemble while Alfred arrives to confront Taylor. Alfred notes that Taylor has destroyed himself, just as the attorney predicted. He's heard rumors that Taylor gossiped about Tennyson's wife and betrayed his honor. A flustered Taylor doesn't believe it's possible. The clock strikes the hour and Tennyson emerges from the basement. The club members applaud him but he says nothing and holds out his hand to Taylor for the money. The colonel is forced to admit that he is a fraud and has no money, and couldn't have even paid Tennyson the $6,000: he lost his fortune years ago. He confesses that Tennyson has proven he's the more substantial of the two of them. Taylor plans to resign but a furious Tennyson grabs the colonel in anger, still not speaking. Finally he takes out a pad of paper and writes down his explanation: he knew he couldn't go a year without speaking so he had the nerves to his vocal cords severed.