Shortly after 'The Cutie Re-Mark'...
"I don't believe this!" Rainbow Dash screams in the Cutie Map room at Twilight's castle. "After all she's done, we're just... forgiving her?"
"I know it's not ideal," Twilight sighs. "For any of us. But I really don't think there's another way to reform her. Maybe offering her friendship is just what we need to help with this. I mean, it worked with Discord."
"Discord's different," Fluttershy mutters. "Everything he ever did he put back to normal on his own. We had to force Starlight to make things right."
"I know," Twilight starts. "But..."
"For once, I agree with Rainbow Dash," Rarity states. "We can't accept just any pony into our group. Besides, there aren't enough Elements for her to represent one."
"She's right," exclaims Applejack. "There are only six Elements. We're about to admit a seventh pony into the Element group. One of us would have to give ours up. And I sure don't want it to be me."
"Me either," Pinkie harrumphs. "I can't even imagine that stuck-up Starlight smile, let alone laugh."
"I can't imagine her being kind to innocent creatures," Fluttershy whispers.
"I can't imagine her busting clouds all day," Rainbow shouts. "Or being loyal to her friends in any way!"
"Hey, that rhymes!" Pinkie giggles.
"Well, I for one can't imagine a high n' mighty unicorn like herself to do any hard, honest work on my farm," Applejack argues. "Er, no offense, Rarity."
"None taken. And I for one can't even begin to think of her being generous to all of her friends," Rarity smirks.
"Well, Twilight, it looks like we've ruled out all of the Elements. Looks like she's gonna have to get the boot," Rainbow says. "I volunteer to do the booting."
"No pony is giving any pony the boot," Twilight says through gritted teeth. "You've forgotten one Element, and one that she would fill quite well. And after seeing that none of you are willing to even give her a chance, I'm not too reluctant to do this anymore."
She turns to the hall and shouts, "Spike, take a letter!"
"Sure thing, Twi!" Spike dashes into the Cutie Map room and pulls out a scroll. "Ready when you are, Twilight."
"I, Princess Twilight Sparkle, hereby decree that you, Starlight Glimmer, shall fill my position as the sixth Element of Harmony, the Element of Magic."
Every pony in the room's jaws drop, including Spike.
"I'm not done yet. I also decree that I shall permanently retire to the castle in Canterlot, only to stop by when requested by an authority figure."
"No, Twilight, you can't do this!" Rainbow screams. "We're sorry! Spike, stop writing!"
"I can't!" Spike yells. "Something's forcing me to!"
"Send it to the castle, Spike," Twilight says, robotically, as if in a trance.
"Don't send it!" Applejack yells. "If you do, it's all over!"
"It's like she's under a spell," Rarity hollers, waving her hoof in front of Twilight's face, her eyes glazed over.
Meanwhile, Spike raises the scroll to his mouth, and is ready to spout fire.
Fluttershy grabs him and throws him up to the ceiling.
As soon as he hits the ceiling, however, the flame is let loose, and the scroll is sent.
"Goodbye, every pony." Twilight starts walking towards the exit.
No pony stops her. It's too late. The decree has been sent.
A few seconds after she had left, a familiar figure graces the entrance.
"I heard noises in this room, and I came to see if everything was alright. I saw Twilight leaving when I came down. Is everything okay?" Starlight Glimmer had a look of worry frozen on her face.
"How the hay did you get here so fast?" Rainbow shouts.
"I was in the area," Starlight says. She grins and says, "Is there anything I can do to help?"
The remaining five friends all glanced at each other. "Now that you mention it..."
~~~~~~~~~~~~~~~~~~~~~~~~~~~
While every pony in the room was shouting at Twilight to stop and destroy the decree before it was too late, no pony had noticed a shadowy figure lurking in the hallway, her horn alight with blue magical flame.
Coincidentally, this same flame was surrounding the princess, as well as Spike's writing claw, although no one in the room seemed to notice or care.
Upon closer inspection of the figure, we can see Starlight Glimmer aiming her energy at Twilight, and whispering, "It's all part of the plan..."
As the entranced Twilight exited the room, Starlight realized that she couldn't just send her on her way. Then she would just come back and ruin her plan. So, in a fit of last-minute genius, she wiped Twilight's memories and sent her to the castle using her highly effective teleportation techniques. Not just any room in the castle, however. She sent her to the Caves beneath Canterlot, a once-famous prison where Twilight had actually been before when defeating Queen Chrysalis. It had taken the aid of Princess Cadence to free her then, and now, without her memories, it would be nearly impossible for her to escape.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~
"She'll never bother us again," she says to her new-found friends as they all retell the tale of what had happened in the meeting.
"But we want her to come back, Starlight," Fluttershy sobs. "She was our best friend."
All of the others cry in agreement.
"But she abandoned you," Starlight says. "Can you still call her a friend?"
All of them think about this for a moment. "No... I guess we can't, can we?" Applejack says.
"It was completely uncalled for," Rarity admits. "But isn't the point of being a friend to forgive the other when they make a mistake?"
"A mistake?" Rainbow says, furiously. "She practically issued a royal decree that we weren't to be her friends anymore!"
"It was pretty rude," Fluttershy says.
"Then why don't we all just forget about that rude princess?" Starlight engulfs all of them in her magic.
"Who were we just talking' about?" Applejack says, rubbing her head. The spell was cast.
"Why were we all crying?" Pinkie inquires. "Crying isn't fun at all!"
"See?" Starlight brought them all in a group hug. "You're all feeling better already."
Author's Note
I wrote this in a fit of thinking of the next season of MLP. I mean, for all we know, this could be what happens next! Although that would be highly unlikely.