It was a cool, spring day, and the playground was domed by an overcast sky when the boy saw the old man. The old man went around a corner, and the boy used a game of freeze tag to distract the girl, while he went around the corner with no one looking. There, the old man sat upon an old bench.
"You can't be here," said the boy.
"You're right," said the old man. "That's why I'm not actually here. What you see before you is an isomorphic projection from another timeline - a future that you won't experience."
"That sounds made-up."
"And yet, here I am. You recognize me, sitting here, as well as I recognize you, standing there."
The boy raised an eyebrow and asked, "Why isomorphic?"
"It's as much to provide clipping as anything else."
"So, why are you here at all? What's wrong with the future?"
The old man stared past the boy, into the distance. "In the future, I realized that there's no going back. I wasted this life. I failed to do the one thing that was most important, the one reason why I went back in the first place." Here, he paused, for his words were difficult to say, though he knew that he must say them. "You don't really love Jamie, you know."
The boy looked down to the ground, the guilt heavy on his heart. "I know."
The gasp caught the boy off guard. He turned to see what he already knew was there. Seeing her tears only made it worse. He reached, and he stepped, but she turned and she ran. He turned back to the old man, then back to where she had been, then back again, at a loss for a correct course of action.
"You have to go back," said the old man. "There's nothing for us here." Without a sight or a sound, the old man disappeared.
The boy hesitated for a moment, wishing only that there had been another way - not that he hadn't appeared to himself to tell himself what he already knew, but that things had just been different, somehow. ... He closed his eyes, and the world disappeared.
The young man awoke, and, for a time, all that he could do was cry.