Warning: Wikipedia contains spoilers.
The film is set in the United States during the 1950s. Peter Appleton (played by Carrey) is an up-and-coming young screenwriter who is accused of being a Communist. His career in ruins, he gets drunk and gets into a car accident. When he wakes up, his memory lost, he is in a small town called Lawson. The townsfolk believe him to be Luke Trimble, one of the town boys killed in World War II. "Luke" settles in to "his" old life, and with his "father" Harry (Martin Landau), start to rebuild The Majestic, an old movie theatre.
The movie was not particularly well received by the critics. (For example, Kenneth Turan of the Los Angeles Times commented that it was a "derivative, self-satisfied fable that couldn't be more treacly and simple-minded if it tried.") Its Capra-esque quality was also noted by a number of critics.