After the apocalypse, the last person on Earth sat alone, there was a knock at the door. The last person on Earth didn't recognize the sound for what it was, at first. Memories of knocks and open doors and other people had been so traumatic that the last person struggled to reel them back from wherever they'd been drowned.
Not without a little fear, the last person opened the door. There was someone there who looked exactly like him.
"Who are you--," he began to say, but the person in front of him copied him exactly! It looked like a man, with wrinkled but pale features, as though he had been living underground just like the last person on Earth. The last person reached out to touch the man, less and less surprised at how similar their clothing was, the man copied him exactly!
Their fingers touched, cold and smooth, the last person on Earth fell to the floor as the man did as well.
The last man on Earth slammed the door hard on the mirror. He shuddered with returning knowledge, he was a man, not a person, a man.
Without women, there was no hope for the race, without women, a man would rather die than pretend to live.
Only as a person could he endure it.
After a great, indefinite amount of time, the man forgot about the hallway closet by the stairs with the unbroken mirror hidden inside it, that rare cursed treasure in this apocalypse where nothing, not even this house he grew up in, remained whole and intact.
He forgot and became a person again.
Then one night, when the loneliness became unbearable, the last person on Earth heard a knock...