"In the vernacular of space, this is T minus one hour, sixty minutes before a human being named Major Robert Gaines is lifted off from the Mother Earth and rocketed into the sky, farther and longer than any man ahead of him. Call this one of the first faltering steps of man to sever the umbilical cord of gravity and stretch out a fingertip toward an unknown. In a moment, we'll join this astronaut named Gaines and embark on an adventure, because the environs overhead - the stars, the sky, the infinitive space - are all part of a vast question mark known as the Twilight Zone."
An astronaut, Major Robert Gaines, is orbiting the Earth in his space capsule. Suddenly, his communication systems stop functioning and he blacks out, waking up on Earth with no memory of his return. He appears to be none the worse for his experiences and is released to the custody of his family.
However, inconsistencies quickly pop up. His daughter senses that he is not the same person. His house has a white picket fence that he's never seen, though his wife insists that it was there when they bought the house. Everyone calls him Colonel (confirmed by the rank insignia on his uniform) when he knows he's a Major, and he insists that the President of the United States is John F. Kennedy, a man no one else has heard of. Gaines concludes that he must have slipped into a parallel universe and tries to return to his space capsule, but blacks out again before he can do so.
He immediately finds himself back in orbit and lands his craft safely. He is prepared to write the whole thing off as a nightmare, but controllers on the ground subsequently receive another transmission — from Colonel Robert Gaines…
"Major Robert Gaines, a latter-day voyager just returned from an adventure. Submitted to you without any recommendation as to belief or disbelief. You can accept or reject; you pays your money and you takes your choice. But credulous or incredulous, don't bother to ask anyone for proof that it could happen. The obligation is a reverse challenge: prove that it couldn't. This happens to be... the Twilight Zone."