Scientists Michael Brace (Christopher Walken) and Lillian Reynods (Louise Fletcher) are inventors of a device that can record and then play back the experiences of people.
On further experimentation it can also record memories and emotions. Walken uses the machine as a way of recording his memories into a "love letter" to his wife, Karen (Natalie Wood) thus bringing them back together. In fact, she's the designer whose job it is is to make the device wearable, like a pair of headphones.
Their boss is Alex Terson (Cliff Robertson), who sees dollars signs with this groundbreaking invention. He lets the government in on this and they begin the military applications of it, such as training fighter pilots. They also begin do bad things with it, like recording the experiences of the mentally ill people. What reason they do this for is later alluded to in the movie. Late one night, when Lillian has a heart attack, she has mind enough to hook herself up to the device and record her experience of dying. She leaves it for Michael but he only has a chance to see the beginning of it. When it puts him in the hospital his boss takes him off the project and moves it to another facility. But he's determined to watch the recording to the end and has to go to great lengths to break in and retrieve it.
This is a very cool movie, I think the first to deal with "virtual" reality in any real way. Even though some things are antiquated, such as the computer reels and the way in which they have to physically splice the memory tape (this is before "digital media"), the story holds up quite well for being 27 years old. I liked this movie when I saw it long ago and I still like it now.