"I can't believe it," said the girl as she stared at the boy in front of her. "It's really you."
The boy smiled. "I told you I'd find you again."
The girl shook her head. "But how? I thought you were from the future."
"I am," said the boy. "But I have the power to travel through time, just like you."
The girl's eyes widened. "How do you know about that?"
"Remember when we first met?" said the boy. "You were about to go back in time to save your friend from a car accident. I stopped you because I knew you would succeed and I didn't want to change the future."
The girl nodded. "I remember. But that was the only time I've ever used my power. I haven't been able to do it since."
"I know," said the boy. "It's because you're not supposed to change the past. But I'm from the future, and I've been changing the past to try and make a better future. But it's not working. Every time I change something, it just gets worse. That's why I came back to find you. Maybe together we can figure out a way to fix things."
The girl thought for a moment. "Okay," she said. "Let's try."
So the girl and the boy went back in time to the moment the girl's friend was supposed to have the car accident. But instead of stopping her friend, the girl used her power to make the car swerve out of the way.
"What are you doing?" the boy cried.
"I'm saving her," said the girl. "Just like you did for me."
But as soon as she changed the past, the future began to change as well. Soon, they were in a world where the girl's friend was never in a car accident, but she was hit by a bus and killed instead.
"No!" the girl cried.
"I told you this wouldn't work," said the boy. "You can't keep changing things. You have to let the past be."
The girl shook her head. "No. There has to be a way to fix this. We just have to find it."
And so the girl and the boy kept travelling through time, trying to change the past to save the future. But no matter what they did, they couldn't seem to make things better. The more they changed, the worse things got.
"It's like we're stuck in a loop," the girl said one day. "No matter what we do, we can't seem to make things better."
"Maybe we're not meant to," said the boy. "Maybe we're just supposed to accept the fact that some things are meant to be."
The girl shook her head. "No. I refuse to believe that. There has to be a way to fix this. We just have to keep trying."
And so they continue to travel through time, trying to make a difference. Maybe one day they'll succeed. Or maybe they'll just keep going around in circles forever.