Twilight thought she had gotten used to surprises after being friends with Pinkie Pie for so long. Coming home from errands to find her parents and Princess Luna waiting in her throne room was still a shock.

"Mom, dad, Princess... what's going on." All three of them looked uncomfortable. They fidgeted, and never met her eyes for long.

Twilight sat down. "Is everything okay?" Her heart beat faster as a sense of dread began to rise out of her stomach.

Luna spoke first. "It's just something that should have happened a long time ago."

Twilight Velvet put on a fake smile. "No, don't worry, everything is fine. We just need to have a little talk, that's all."

"Ridiculous, rather," Luna said.

"O-kay," Twilight said. Their attempts at reassurance did nothing for her fears.

"It's a talk everypony has at some point. And I know we should have sat down with you sooner, but there was just never a good time for it, and you were always so excited that we didn't want to—"

Luna cleared her throat.

Velvet winced. "Ah, well, you see, it's Celestia. She isn't real, honey."

"I don't have a sister. Ponies just assume there is a sun princess because I rule the night."

Twilight stared. Either she had gone mad, or her mom had. She wasn't sure which possibility she was more afraid of. "What in Equestria are you talking about? She was my [i]teacher[/i]. She's a Princess, she makes the sun rise." 

Luna stared at her. "Twilight, the sun is too big to move. You are an expert in magic, you know this."

Velvet shook her head sadly. Night Light wrapped a hoof around her. "This is why we didn't want to tell you. We knew you'd be so disappointed. But she's just a story."

"A stubborn one too. Though [i]usually[/i] harmless. For ponies who have real observational and logical skills."

"You guys are kidding, right?" Twilight kept looking back and forth between them. There was nothing but sincerity and regret in their faces.

She held her head in her hooves. It didn't stop the world from spinning. "That's not possible. I've met Celestia. If she's not real than who was my teacher? Who sent me to Ponyville?" She waved a hoof around. "I'm here, I have all this because of Celestia. How can she not be real?"

"It's us, Twilight," Night Light said. "We've been dressing up as Celestia for you."

"How you ever believed it is beyond me," Luna said.

"That's... that's not possible." Twilight had to grip the table to stay upright. In her head was a neat, organized catalog of every second she had spent with Celestia. She began reviewing every bit of her mental archives for any signs of the truth. Twilight shook her head. "No. No, no, nonono."

"It was just my former friends who banished me. You know, the ponies whose descendants ruled for the millennium I was gone?" She conjured an image of five ponies facing her in battle.

In response, Twilight's parents levitated an empty costume from behind their seats. The set down the expanse of white fabric in front of Twilight. The head looked at Twilight with bright purple eyes. She stroked it with her hoof. "I can't believe it. I'm the only princess in Equestria and nopony even told me."

"Excuse me?!" Luna said. Her mane billowed angrily.

"We're very sorry," her parents said. "We didn't mean to lie to you. Celestia is just supposed to be something fun for foals, like Santa Hooves. But you were so caught up in it we didn't have the heart to tell you the truth. Not until Luna made us come down here." They were hugging each other.

"Something I should not have needed to do," Luna said. "And what did you mean, 'only princess?' There are three more."

But the end of their explanation had been lost. Twilight had stopped listening halfway through, her mind caught on the horrible words that rang in her ears like shattering glass. "What do you mean, Santa Hooves?"