Joanna Eberhart (Nicole Kidman) is a top New York TV executive who specializes in reality TV shows in which women get the better of men, especially wives of their husbands. After the launch of a tropical island fidelity test show in which the man spurns the temptations to stay with his wife, but she abandons him in favour of the muscular alternatives she's had all week, the husband turns up with a gun at Joanna's big corporate new season presentation, so of course all the lawyers and shareholders get nervous, the shows get pulled, and Joanna gets fired and has a nervous breakdown.
Her husband Walter (Matthew Broderick), a junior executive in the same TV company who went there only to work for her in order to see her sometimes, retires too, and takes the family (they have two children) to live in the superficially ideal, affluent yet leafy little gated town of Stepford, Connecticut. They notice that the husbands are all very content ... and the wives too, but in a hyperdomestic way. Joanna recovers, gradually, and complains to Walter to the effect that the men are all nerds and the women all Barbie dolls. The only (to Joanna) normal woman there is her old friend the fat, very Jewish intellectual writer Bobbie Markowitz (Bette Midler). She and Joanna always wear black city grunge whereas all the other wives --- who are also all blondes with perfect figures and complexions --- wear colourful frocks.
And the men spend all their time at the Stepford Men's Club, but expect their wives to be at home all the time, washing laundry, cleaning, and making endless batches of cakes while they wait infinitely patiently for their husbands to come home to be fed and then seduced in the bedroom (yes, even in the middle of the day as the outsiders discover). Bobbie and Joanna start to investigate; but then Bobbie undergoes the transformation to blonde houseproud home baker in blue gingham, and Joanna is on her own.
In the end we all find out the secret of Claire (Glenn Close) and Mike Wellington (Christopher Walken), the town's rather spooky, leading "ideal" married couple. At first, Claire appears as the realtor introducing Walter & Joanna to their new house; then she takes Joanna to the ladies' keep fit session, where Claire is the instructor (all the ladies exercise in their usual frocks and full makeup). Mike is like town mayor; and that isn't actually his name: he's called Mike because he used to work for Microsoft ...
It's at the town picnic, when one woman overdoes the barn dancing and Joanna sees sparks coming out of her ears but Mike won't allow anyone to call an ambulance, that Joanna is first seriously spooked. Meanwhile Walter's amazed by the other men's contentment. He's even more amazed when a man summons his wife and asks for twenty dollars. She sticks his cash card in her mouth and then spits out first the card then twenty one-dollar bills.
Conclusion: the woman have been quietly converted into robots, all except Claire. We finally discover she is the brains behind the whole town and that Mike (who does have very synthetic-looking stawberry blonde hair) is the robot.