Driving back from a weekend in London, Richard and Janet Gayford are surprised to find the village of Midwich sealed off because of 'army manoeuvres'. There are no birds singing, the air seems thick and there is a strange sort of music in the air. It soon becomes clear that there is an invisible wall around the village, and everyone within the perimeter is unconscious. When the barrier lifts, the strange occurrence is put down to a gas leak.