A series of inexplicable events are taking place around the world. In Indiana, electrical lineman Roy Neary has a close encounter with a UFO, an experience that leaves him sunburned. The phenomenon messes with electronics and bewilders the community. Concurrently, other individuals experience similar encounters, including single mother Jillian Guiler, whose young son Barry is drawn to the mysterious happenings. These events are echoed globally when a French scientist, Claude Lacombe, and his American interpreter, David Laughlin, investigate a lost squadron of World War II airplanes that mysteriously reappeared in the Mexican desert, fully intact but without their pilots.

As Roy becomes obsessed with the visions of a mountain-like shape triggered by his encounter, his behavior becomes increasingly erratic, straining his relationship with his wife Ronnie and their children. Roy's and Jillian's lives intersect as they both seek answers to the strange happenstances that seem to connect them to the otherworldly visitors. Their need for understanding pulls them toward a common destiny, guided by a series of psychic visions and encounters with the UFOs. Meanwhile, Lacombe and his team decipher a series of signals received from outer space, leading them to organize a secret meeting with the visitors, hinting at a deeper purpose behind the encounters.