'Those people are our neighbours.'
This episode is one of the most terrifying ever written for the Twilight Zone - and there isn't a supernatural element in it. Precisely what makes it so disturbing is that the scenario Serling poses seems to be all too possible, and was possible in the Cold War era of the atomic bomb.
The episode opens with the celebration of the local doctor Bill Stockton, played by Larry Gates; a gathering of nuclear families and the exchange of normality and pleasantries, soon to be broken by a radio broadcast warning of UFOs converging on America. As panic sets in, each of the families leave to retreat to their homes and gather supplies. But the good doctor has something the other families do not - a bomb shelter. The other families plead with the doctor to let them in, but he refuses and events quickly turn nasty as the veneer of normality observed at the opening dinner quickly evaporates.
This 'exercise' as Serling likes to call it is one of his most powerful studies of human nature. The episode examines what happens when humanity is faced with its extinction, and Serling's answer is a troubling, pessimistic one. The families turn on each other with startling, uncivilised ferocity and the imperative becomes not just to survive, but to destroy others to live. Ugly prejudices rise to the surface; pointedly the suppressed xenophobic discourses of post-War America are directed at one of the characters described as a 'semi-American' by one of the men and his wife, who moments before were so amiable. Eventually two of the men decide to destroy the shelter door and they succeed seconds before another announcement is made, declaring the UFOs as harmless satellites.
What happens here is another disturbing idea: the families want to return to normal. The husband who barely minutes before had assaulted the 'foreigner', Marty, defends himself by protesting his fear of death, and Marty himself suggests a party despite the racial and physical abuse he has suffered. They all want a celebration - a performance of normality - apart from the doctor, who is appalled by what he has witnessed, and who suggests that normality, really, is the mob that almost tore itself apart to survive. Normality the episode suggests is a construct, a way of papering over the cracks and prejudices, joining in a false unity which evades the knowledge that you might not know your neighbours as well as you think, and that put in the right (or wrong) situation, they would destroy you to preserve their own lives. It is only the doctor who was prepared for the very possibility of a nuclear or bomb attack - and the disruption of normality -, and acknowledges that he might well have seen the neighbours in their true colours. The resonance of the episode is produced precisely as Serling forewarns: it is unsettlingly close to home, to the neighbours you may not fully know.