"No."
It surprised herself almost as much as it surprised Celestia. Twilight withdrew her hoof suddenly, and planted it back on the cobbles.
"No."
Celestia's jaw dropped. It took a lot to shock a 2,513 year old, but this about did it. Her magical grasp on the little box failed and it dropped, the little golden tiara tinkling across the flagstones.
"No?" was all Celestia could think to say. "Why?"
"Because..." Twilight glanced about. "Because..."
Luna stood by Celestia's shoulder and offered no answers, implacable as ever. Lilac crept around the balcony's balustrade, and the smell of it filled the air. In the west, the sun shone low and warm, and still Twilight Sparkle needed to explain herself. She took a deep breath.
"Because why should I?"
Celestia recovered admirably. She broke out into her most regal smile. "Because you have always been destined for greatness, my faithful student."
Twilight looked down at the tiara, lying where it fell, and her cutie mark stared back. "Me, and only me," she said, quietly.
"You'll still have your friends, " said Celestia, still beaming her smile down. It wasn't a magical smile, but it was... reassuring.
Twilight looked up at the two princesses; Luna, shorter and slighter, and Celestia, taller and prouder. They were sisters born and bred, perfectly matched. Made to order. Made to last. A thought occurred to her, and fear ran down her back like an ice cube.
"But... But I'll still... I mean, I'll see them die."
Celestia's smile didn't falter, it just shifted a little. "But not for a long time yet."
Twilight swallowed heavily, as the image of five headstones came into her head. Five headstones, and her by herself. She'd have the Princesses, though, and Spike. She could live forever and forget who she was, and who she had been.
Her breathing became heavier.
"B-but the kingdom-"
"Will continue with you much as it has without you."
Twilight risked a glance at Luna, who avoided her eyes. Long was the shadow she cast...
"I-I can't," she stammered. Her knees went weak.
Celestia took a step forward. "My faithful student," she repeated, "you were always fated to rule with us."
"No!" Twilight shouted. "Y-you don't understand, I can't!"
"Twilight, I know you're scared, but I know what you must be thinking-"
"You were born an alicorn!" Twilight blurted out. "You knew, whatever else, you were going to be a Princess and a godess! I... I never even thought I'd... All my life I ever wanted to do was learn."
"And you have learned. This is the opportunity to put that to use! Think of it as a reward."
"No!" Twilight drew back. "I won't."
"Twilight, you are the greatest magician of the generation, perhaps the greatest the world has ever known. Don't throw that away."
Celestia picked up the tiara with one hoof and advanced on her pupil.
"S-so that's it!" said Twilight, moving towards the balcony's edge. "You want me preserved, your failsafe, in case something goes wrong!"
Celestia's face hardened. "I would never want that."
Did she hesistate, just for a second? Twilight thought she heard hesitation. She shuffled back again, but met the balustrade. She glanced over her shoulder and saw the thousand foot drop. They said there was a great magical field which meant no one ever fell to their deaths, but if there was it was very old, and must be very worn. Her breath caught in her throat.
She looked back at Celestia, who was still advancing on her, tiara in hoof.
"Twilight, now is your chance!" she said.
She made a decision. "NO!"
And like that, she stumbled over the balustrade.
Celestia's heart leapt into her mouth. A veil lifted from her eyes, and she rushed over to the edge, peering into the air below the castle.
"TWILIGHT!"
But she wasn't there. Celestia took off the balcony and flew down as fast as she could. Terminal velocity for somepony of Twilight's size can't have been great, and Celestia was a damn good flyer, but Twilight was gone.
"Wh-where...?" she looked around, hovering puzzled.
Luna was waiting on the balcony, her face set. Celestia landed, her head drooping.
"She's gone, hasn't she?"
"I didn't think she'd-" Celestia started.
"No, you didn't think, did you?" said Luna, sharply. "What did you expect to happen, that she'd just roll over and accept whatever you told her to?"
"She was always such a good student. She could have been so much more, Luna."
"So could anypony. Will you give them sisterhood too?"
Sadness comes easily to immortals. Celestia collapsed into her sisters hooves and sobbed quietly. Luna realised she'd overstepped a mark. She put a hoof around her sister's shoulders.
"What's done is done," she said. "Come on."
Together, the sisters walked back into the palace. The tiara lay where it had fallen, innocent as a loaded gun.
A quick diversion on unicorn teleportation is called for at this point.
It has already been said that it's one of the most useful things ever invented by ponykind, despite also being one of the most mysterious. Matter is transported from point A to point B with no damage or any adverse effects of any kind (except for when it arrives smelling faintly of jasmine), but exactly how remains a mystery. One of the most curious facts about it is that matter retains any acceleration it might have had before teleportation. In the words of the great magician Starswirl the Bearded, 'speedy thing goes in, speedy thing comes out'.
This is why Twilight Sparkle hit her bed in the palace's visitors' suite at something like forty miles an hour. Luckily, it was very well aired and filled with the finest down money could buy. It still split and burst, but it was a soft landing at least. She lay for a while among the spars of wood and drifts of white feathers in a state of dazed calm. She took a few deep breaths, the memory of wind in her hair only just fading. Then she remembered what she was doing.
She leapt to her hooves. Time to complete the escape. Another time, the room might have reminded her of late-night chats with the Princess over cocoa, tea, and coffee, but none of that occurred to her now. Spike was sat in the middle of the room, giving her a wide-eyed stare.
"SPIKE!" she said, making him jump and come to attention. "Get your stuff together, I need to get back to Ponyville now!"
She waved a hoof in front of her face to clear the feathers and levitated her suitcase and started packing. Or at least throwing things into it. Her room was a mess at the best of times, but at least everything was close to hoof. Spike, meanwhile, was just getting to his feet. He recognised the signs of early-onset freakout.
"Twilight, are you okay?" he tried.
She didn't turn around to answer him, but clicked her suitcase shut and said, "It's no good, you'll have to catch up."
"Twilight, I think you should calm down."
She turned suddenly and fixed him with a glare. He flinched.
"I. Do not. Need. To calm down," she said. "Now is the perfect time for panic."
She rushed over to the door, suitcase levitated beside her.
"If you see them, tell them..." she paused, glancing around. "Tell them I don't want to talk to them right now."
"Who?" said Spike.
"The Princesses!" Twilight shouted. She let out a groan and rushed out of the door.
Spike, meanwhile, considered his options. He could try and decipher some kind of sense out of Twilight's ramblings, or he could have a lie down and forget all about it. Or, he could go after her, and make sure she was okay.
He cast a rueful look at his bed.
"She's lucky she's got you around," he muttered to himself. With that, he ran out of the door, shouting after her.
Shouting got the Princess' attention. Years of crisis management had given them both an instant reflex to shouts, yells and screams of all kinds; breakneck running to find out what it was before it killed, ate, or otherwise inconvenienced anypony.
They ran down the hall until they saw Spike, who was going as fast as his little legs could carry him. Celestia caught up with him first.
"Spike, what's wrong?" she said. "Has something happened?"
He came to a stop and looked up.
"Tw-twilight just-" He took a deep breath. "Twilight just ran off."
The sisters shared a glance.
"Which way?" said Celestia, urgently.
"She seemed pretty upset about something..."
"WHICH WAY?"
Spike jumped in surprise and pointed a claw. The Princesses hared off down the hallway.
Twilight was beginning to regret her vocation. Applejack could run a mile, buck an orchard and still cook a meal for herself afterwards, while Rainbow could make a mile in thirty seconds. Twilight though, whose most strenuous exercise was hauling herself out of bed in the morning, was exhausted after only three (maybe four) corridors of panicked fleeing. She was puffing and panting and her limbs ached but she was crystal-clear in her need to escape.
Then, she heard a crash of brass and steel on flagstones behind her. She willed her underworked legs to keep going, but they revolted by developing the worst cramp in the western world. She limped on as best she could, she could hear them drawing closer. She stumbled and leaned up against the wall to catch her breath. Any minute, they'd round the corner. Any minute, they'd-
"TWILIGHT!"
She turned slowly and saw Celestia barrelling down the corridor to her, head down, her eyes flashing with-
Tears?
OOF!
Celestia hit her like a freight train, wrapping her hooves around her. Twilight writhed a bit, but the hug wasn't malicious.
"Oh you're alive!" said Celestia, breathlessly. "Thank goodness..."
Luna came up into Twilight's line of sight. She mouthed 'don't worry' and shook her head.
Celestia let go and Twilight settled back onto the flagstones, a little unsteady.
"I'm, ah, sorry, Twilight," said Celestia, keeping her head up as regally as she could muster. "I shouldn't have... well, anyway. The choice should be yours, ultimately."
"Er, thank you," Twilight said, tensing for a storm that wasn't breaking.
Celestia smiled out the corner of her mouth. "In your own time, of course."
There was a pause. Twilight became very aware of Luna giving Celestia a sidelong look.
Celestia coughed. "I should be going now," she said. "I, er, hope to see you again soon."
Twilight bowed her head on relflex, and Celestia swept back down the corridor. Luna stayed and looked down her nose at Twilight, who shrank back a little.
"I apologise for my sister," she said, quickly. "She has your best interest at heart, but she can be a little highly strung at times."
She chuckled. "I think you gave her quite a fright."
Twilight gave a forced little 'hah', followed by a long sigh. She felt like she'd swallowed a bowling ball. "I just... I don't know what I should do."
"Don't let it get to you," said Luna. "Remember, you don't have to make this choice on your own. You have your friends and family."
"Right," said Twilight, biting her lip.
"And, if you ever need any help, I'd more than happy to provide."
Twilight nodded. "Thank you, Princess. I'll... I'll consider it."
Luna smiled broadly. "We couldn't ask for more."
Celestia waved Twilight off at the station in the end. It was a nice gesture, so Twilight waved back, smiling as best she could as the train wheezed into motion. The Princess seemed to have recovered a little by then, and her old smile had come back as they had walked down the cobbled streets. Luna was smiling warmly from the platform, not waving, but giving Twilight a look somewhere between approval and support. Twilight watched them as the train pulled out, taking her back to Ponyville. Then, when they were out of sight, she sat back in her seat and took a deep breath.
"What a visit," said Spike, maybe a little too archly. "It'll be good to be back home again, huh?"
Twilight nodded slowly.
Spike smiled up at her, tentatively. "I mean, the town's probably gone crazy without you."
"Oh come on, what's the worst that could happen?" said Twilight, smiling.
"Well, Apple Bloom, Scootaloo and Sweetie Belle have probably gotten up to something, Fluttershy'll be having a panic attack, Rarity'll be being a drama queen, and Pinkie Pie will be-"
"Being Pinkie Pie?"
"Exactly!" said Spike. "We gotta get back and make sure things don't get any worse."
Twilight giggled. "Spike, c'mon, we've only been gone a day."
"Yeah, but since when's that stopped them?"
Twilight laughed and gave Spike a playful shove. He shoved back grinning and, for a moment, as the train rolled down the mountain towards Ponyville, Twilight could forget about the small plain wooden box in her luggage. The one containing the tiara, with the six-pointed star picked out in amethyst.