Visit to a Small Planet is a science fiction film that centers on an alien named Kreton (Jerry Lewis). He is curious about humans and frequently visits Earth, much to the chagrin of his teacher, Delton (John Williams). Eventually, Delton allows him to stay on Earth to examine the behavior of humans. He stays with Rheba (Lee Patrick) and Major Roger Putnam Spelding (Fed Clark), a suburban couple, who know about Kreton's secret, but decide to keep it to themselves. Problems arise when Kreton begins to develop feelings for the Spelding's daughter, Ellen (Joan Blackman). Because Kreton's race has forbidden any displays of affection, he is not able to have any physical contact with her. Kreton has broken Delton's rule not to get involved in the humans' lives, so he strips Kreton of his powers, hoping he will see what it is like to be a human. What Kreton soon discovers changes his outlook on the human race.