Fluttershy was at home, sleeping, when she heard a knock on the door. She walked over and opened it and saw Twilight and Rainbow Dash standing there.

"Oh, hello Twilight. Hello, umm..." Fluttershy paused for a moment while she thought. "I'm sorry. I really am. I'm trying to remember you, but I can't."

Rainbow Dash's head dropped.

"Hello Fluttershy. We're sorry to disturb you, but we really need your help." Twilight said
"Oh, well, what can I help you with?" Fluttershy said, slightly confused
"Okay, Rainbow Dash has been feeling a bit down since the other day in the hospital, so we were wondering if you wouldn't coming with us for a few hours to try and jog your memory."
"Umm... Okay. What's the worst that could happen? Right?"

Author's Note

To answer Fluttershy's question, the worst that could happen is:
They somehow create a paradox which destroys the time-space continuum and erases every point in time and space to the end of the universe, in every universe, so then nothing would of ever existed anywhere at any point in time in any universe or dimension. Plus, while it's happening, every single pony, past, present or future, is being destroyed with EXTREME PAIN AND TORTURE!