A fatigued man fights to stay awake as he explains to a psychiatrist that if he falls asleep it will trigger a nightmare, which will cause his heart to fail.

Twelve o'clock noon. An ordinary scene, an ordinary city. Lunchtime for thousands of ordinary people. To most of them, this hour will be a rest, a pleasant break in a day's routine. To most, but not all. To Edward Hall, time is an enemy, and the hour to come is a matter of life and death.

They say a dream takes only a second or so, and yet in that second a man can live a lifetime. He can suffer and die, and who's to say which is the greater reality: the one we know or the one in dreams, between heaven, the sky, the earth - in the Twilight Zone.