High-schoolers David and his twin sister Jennifer lead very different lives: Jennifer is shallow, popular and outgoing, while the introverted David spends most of his time watching Pleasantville, a black-and-white 1950 sitcom about the idyllic Parker family. One evening while their mother is away, David and Jennifer fight over the television, breaking the remote control.
A mysterious TV repairman arrives and, impressed by David�s knowledge of Pleasantville, gives him a strange remote control before departing. When they use the remote control, David and Jennifer are transported into the black-and-white world of Pleasantville, finding themselves in the Parkers� living room. David tries to reason with the repairman, communicating through the Parkers' television, but the repairman declares that the world of Pleasantville is better than the real world and they should be lucky to live in it.
Forced to act as the show�s characters Bud and Mary Sue Parker, David and Jennifer explore the wholesome but peculiar town � fire does not exist and firefighters merely rescue cats from trees, and the citizens of Pleasantville are unaware that anything exists outside of their town, as all roads circle back with no escape. David tells Jennifer they must stay in character and not disrupt the town. Trying to maintain the show's plot, Jennifer dates a boy from school but has sex with him, a concept unknown to him and everyone else in town.
Slowly, parts of Pleasantville change from black-and-white to color, including flowers and the faces of people who experience new bursts of emotion and foreign concepts such as books, fire and rain begin to appear. After Jennifer introduces sex to her peers, many of her classmates go to Lover's Lane to engage in sex, becoming "colored" in the process.
David introduces Bill Johnson, owner of the soda fountain where Bud works, to colorful modern art via a book from the library, sparking Bill�s interest in painting. After learning of sex and masturbation from Jennifer, Betty pleasures herself while bathing and, upon reaching orgasm, sees color and eventually becomes "colored" herself. Bill and Betty fall in love and she leaves home, bewildering her husband George. Only the town fathers remain unchanged, led by the mayor Big Bob, who views the changes as a threat to Pleasantville�s values, and resolve to do something about their increasingly independent wives and rebellious children.