One morning, the little town of Newnan, Georgia, is thrown into hysteria when a UFO is reported over the nearby lake; even the personnel from the nearby Air Force base is mobilized. The only one remaining untouched by this hubbub is Sheriff Hall, the big and punchy keeper of the local law; indeed, he does not believe in aliens, especially since layabouts like Brennan use the excitement to commit all sorts of mischief. Still, strange things begin to happen to some of the citizens who share his point of view: a barber's chair begins to spin rapidly around its axis – along with its customer – and an ice cream cart suddenly disgorges its entire load onto the street after the vendor makes a joke about the aliens being hungry for his ice cream. The same night, a blackout hits the city. Hall goes on patrol when his rheumatic deputy Allen calls him to retrieve a runaway boy. Arriving at the boy's favorite place, the local amusement park, Hall finds not one but two boys; one of them – wearing a silver spacesuit – turns out to be the runaway, the other perpetually introduces himself as H7-25, comes up with space-related terms like lightyears and spaceship, brandishes a strange device which makes all things around him go haywire, and even enables Brennan to escape on two occasions and Allen to overcome his rheumatism. Still, the sheriff is not convinced – not until the boy irradiates him with what he calls "bio-magnetic energy", enabling him to make a very big trout leap into his hands and a horse talk in English! Meanwhile, however, an ambitious Air Force Captain named Briggs sees his chance with the UFO sighting and the evidence of an alien landing to further his own career. Working without the knowledge of his highly sceptical general, Briggs finally manages to track down the boy – but his attempts to take him away are foiled by the sheriff's hard-hitting fists and H7-25's technical wizard device, as well as Brennan's assistance. Finally, while Hall and H7-25 camp out at Stone Mountain to await the arrival of the boy's pick-up, Briggs and his men manage to kidnap the boy and bring him to the base. The sheriff, however, manages to infiltrate the facility and gets the boy out. In a mass showdown at the local fire brigade hall, where a party was to be held, Briggs and his men get their share from the Sheriff Hall, the little alien and their friends. Later that night, a spaceship comes to pick up H7-25, and he and Hall part ways. But as Hall returns home, he suddenly finds H7-25 sitting in the back of his car – he has managed to get an additional period of leave on Earth to spend with his big friend.
The filming of the scene where the Sheriff and H7-25 first meet was filmed at Six Flags Over Georgia; that location was later reused for the film's sequel, Everything Happens to Me.
