The end of the world (in Equestria, at least) started not with a bang, but a small popping noise.

Just after noon, when the sun had ascended to the highest point in the sky, it vanished, and darkness covered the land.

An event such as this was inevitably noticed.

In Ponyville, the Flower Sisters all fainted. Barnyard Bargains put out their ‘Disaster Discounts! 20% Off!’ sale signs. Blighter the Lamp Lighter began to make his rounds, turning on all of the street lamps.

And once they had checked the train schedule and realized the next train was not due for some time, the Elements of Harmony galloped to Canterlot.

Several hours later, six sweaty mares traveling at a somewhat slower gallop reached the Canterlot castle and the lone Royal Guard standing casually outside one of the towers.

“Thank the stars,” gasped Twilight Sparkle. “We’re still in time! What happened?”

The guard nodded. “Greetings, Princess Twilight Sparkle. Princess Celestia and Princess Luna are—”

“Imprisoned?” gasped Twilight. “Captured? Struck down? Magically incapacitated?”

“—in the attic storeroom,” continued the guard.

“More stairs?” wailed Rarity, looking up at the towering tower. “But we just got up here! Now we have to climb more?”

The guard pointed to a sign on the door.

Royal Metaphorical Storeroom
-
Alicorns Only

“Oh,” said Rarity.

About a million steps later, Princess Twilight Sparkle came to the top of the staircase, having passed several doors with odd nameplates inscribed in golden letters reading Royal Titles H-L and Moonshine Ageing. She paused to catch her breath, which was probably still about five flights of stairs behind her, and looked at the open doorway to a closet. It was really all she could see, because there were two alicorn rumps sticking out of the open door, and a mixed hornlight which filtered back into the small attic room where Twilight was panting.

“Here we— Oh, it’s another box of your stars, Luna. I don’t see why we need so many spares.”

“They’re critical, Celly!” Luna sniffed and there was a rustling sound of boxes being moved around. “So many of them go out each night, I swear I spend half my time plugging in replacements.”

“And the other half plugging in new ones. If you keep it up, eventually the whole night sky will be one bright light.”

“I’m just making up for the ones you let go out while I was indisposed. Proper maintenance keeps things like this from happening. It’s your responsibility to have a regular replacement schedule. Your carelessness probably is going to get your student all upset too.”

“Um… Princesses?” Twilight craned her head from right to left, trying to see around the royal diarchs to what was inside the apparently small room, but all she could see was the ends of the princesses she had not really looked at before and was trying not to look at now. “What are you doing?”

“Oh! Twilight!” Celestia shuffled her hooves and coughed once. “Sorry. Dust. It’s nothing serious. You can go home. We’ll have this all worked out in—”

“Celly let her bulb burn out,” said Luna.

“Bulb?” Twilight redoubled her attempts to see past the one-alicorn-wide door with two alicorns in it. “What bulb?”

“It will only take a minute for me to find a replacement,” said Celestia.

“You said that two hours ago when you went tearing out of court,” said Luna. “The royals were starting to get restless. Seriously, this place is such a mess for somepony who only has to worry about one bulb.”

“Well, if there weren’t so many stars in here, I would have found it by now,” said Celestia in what sounded like a little bit of a huff. “Ah-HA! There we go. Found one.”

“Nay, Celly. That is one of ours. See the wattage rating?”

“Oh, twelve gigawatts. Darn.”

“You need a petawatt bulb or ponies complain about the day being too dim. I thought you were supposed to tidy up in here while I was gone.”

“I was busy, okay? Here, let’s get some of these out of the way.”

Several cardboard boxes floated over the two alicorns and landed in the small attic room Twilight was standing in. She looked down at them, then looked again.

“Red dwarf? Blue-white giants? They’re light bulbs. Are you trying to tell me the stars are just—”

“Not just light bulbs, Twilight,” said Luna. “Lights of the highest quality.”

Twilight took a good, long look at the faded cardboard boxes bearing stickers reading ‘Buy two, get one free’ as well as ‘After Hearth’s Warming Sale’ and ‘May contain lead’ in small print. There were even several lines of Neighponese and Prench, as well as an expiration date several centuries ago visible under the dust.

“Really?” It was the only word Twilight could think of at the moment.

“It is only wise to stock up when there is a sale,” said Luna, floating several more boxes out of the small closet, and then several more, all of which Twilight read as she stacked them to one side.

“StarBrite© Power Twinkle. Constellation quality. Genuine nebula effects.”

“There it is!” cried Celestia, swishing her tail in excitement. “Help me with this, Luna.”

There were more rummaging noises coming from inside the small closet, then Celestia backed up into the attic with an enormous light bulb the size of a pony’s head hovering in her magical field.

“You only have two more in the box,” said Luna from inside the closet. “Should we not buy some spares?”

Celestia shook her head. “They’re good for a few thousand years, Luna. We should be fine for now.”

“This… is the sun?” said Twilight, looking at the enormous light bulb. “You must be joking. Tell me you’re joking.”

“It’s not the whole sun,” said Celestia, somewhat defensively. “There’s the plug, and a very long cord, of course.”

“Don’t dally, sister,” called Luna over her shoulder as the sounds of more rummaging came from the room. “Go replace it before every pony in Equestria panics and thinks I’ve gone Nightmare Moon again.”

“Very well.” Celestia opened the nearby window with her magic and bent down to whisper into Twilight’s ear. “If you’re not too busy and as long as you’re here, could you help Luna tidy up a little? After all, someday you may need to do this.”

Celestia flew out the window and up into the darkness with Luna calling out after her, “Don’t forget to dust before you plug the new one in!” She sighed and looked back at Twilight while shaking her head. “She can be so messy at times, but I love her just the same.”

As Luna (or at least the front half of her) vanished back into the closet, Twilight just sat on her rump and blinked.

“So,” she started very slowly, “the sun is a light bulb.”

“Of course!” declared Luna. “What did you think it was, a giant planet-sized ball of gas and fusion?”

“Well…”

“Here, hold this box of red dwarfs, please.” Another box proclaiming ‘Authentic Chromatic Fading Action!’ floated out of the closet to Twilight. “I might as well sort the shelves while my sister is out. If I go back to court before she gets the new bulb plugged in, the royals will just get all shouty.”

Twilight silently passed boxes of planetary objects and stellar illumination back and forth to Luna for quite some time in the relative darkness of the attic until light burst into the room from the open window.

“Finally!” declared Luna. “And that’s the last box. Thank you, Twilight. Hm…” She floated a light bulb much the size of the previous one out of the closet and asked, “Twilight Sparkle, do you think we should change the moon’s light too? It has been a long while, and these do not last forever. Twilight? Where did you go?”

Several evenings later, the Castle of Friendship was nearly silent in the middle of the night with only the sound of Twilight Sparkle’s quill against parchment and Spike turning the pages of his comic book.

Then there was a pop somewhere up around the ceiling, and the room became significantly darker.

“Oh, fudge.” Spike stood up and put away his comic book. “A bulb blew. I’ll go get a spare.”

“No, I’ve got it,” said Princess Twilight Sparkle. She got up from her studying and took a deep breath before walking to the closet. “After all, I need the practice.”