Joss Whedon's the genius, not me.
Restless Again
I: The Coming Dawn
by Zzilly14

"Never forget what I am?" Dawn repeated. "Do you mean..."

"You are the Key," Joyce beamed.

"Well, yeah. I used to be a green ball of energy. That was so two years ago, Mom."

"Dawnie," the angelic figure proclaimed, "it's time for you to realize your destiny."

"My destiny?"

"You are the Key," she repeated before fading away.

"Mom! Mom!" Dawn screamed, putting her hand on the cracked window. It was then she realized her fingerprints matched the ones she couldn't figure out where they came from.

"What does this mean?" she asked aloud.

It was then she turned around, and realized she was not alone: in fact, everyone she ever knew was cramped into her tiny bedroom.

Buffy stepped forward. "It's time to unlock the secret," she stated happily. "Fulfill your destiny, Dawnie, and be a Key!"

"What am I supposed to do?" Dawn said, afraid of the answer.

"The lock's over there," her sister replied, pointing to the closet door. "Open it!"

Dawn stood frozen, looking back and forth between the people and the door. "But if I do, I might not come back..."

"It's a sacrifice we're willing to make," Xander added.

Willow smiled. "You're a big girl, Dawnie. It's about time you grew up."

The teenager nodded slowly before walking to the door and turning the knob.