The story of some people, one man in particular, who witness a UFO. For some reason, the sighting causes some of them, in particular Roy Neary (Richard Dreyfuss), to continually visualize Devil's Tower national park.
Eventually they are drawn there to witness a the return of the aliens and a trade of one set of guests for another.
What happens in the interim is the real focus of the movie, as Dreyfuss becomes more and more obsessed with the Devil's Tower without really knowing what it is. He loses his job, alienates his friends and eventually pushes the rest of his family over the edge. I found the ending to be a lot less uplifting as an adult than I did as a young teen when I first saw it.
Honestly, I liked this movie better 30 years ago. I don't really need to see it again.