Bixby, Jerome – “One Way Street” (1954)
Very Twilight Zone, this one, but it works for the most part (note that Bixby is also the author of “It’s a <i>Good</i> Life,” basis for one of the best Twilight Zones).
Pete Innes wakes up in the hospital after driving his car off the road, and finds that things are not quite right anymore. The nurse notes that the address and phone number in his wallet were wrong, the phone dial goes from A-123 to J-000, his wife Mary shows up and apologizes for an argument he doesn’t remember happening, the names of their dog and their neighbor are different, and then we move from personal details to the world at large, with the doctors convincing him that he has some form of amnesia, which is why he doesn’t remember the Citizens Protection Law used to keep him under house arrest.
Making peace with this development, Innes even finds himself enjoying the company of his wife, from whom he had been increasingly alienated during recent years. This new, happier life is soon disrupted by contact from one Dr. van Husen, a participant in the Manhattan Project in the old world, and a researcher into parallel universes in this one, whose misfiring experiment resulted in Innes’s displacement. Things kind of fall apart at this point: to provide some incentive for Innes to want to leave this happier life, he begins to sense that his disruptive presence is going to destroy the universe, and so he accepts van Husen’s offer to try the machine on him again. Mary jumps into the machine with him at the last minute, trusting that the other universe’s Mary is making the same choice to stay with her new Pete. Instead of World 1, though, they find themselves in a new, 3rd world (rather skillfully revealed to the reader with Pete and Mary stepping onto an invisible elevator), which mysteriously does not self-destruct and allows them to live happily ever after.