Equestria, Canterlot

Around Midday

It was a typical day in the Capital City of Equestria. Ponies went about their daily routines, such as shopping or catching up with friends. The midday sun painted an idyllic scene, and everything seemed to be perfect.

That wasn't the case for long as a slight tremor shook the ground. It wasn't unnoticeable, but quiet enough that most didn't notice it. Then, a second tremor, this one a fair bit stronger, shook chairs and toppled a few unsteady patrons at the various taverns.

Then, it settled for a slight moment as the ponies in the city looked at each other in confusion. Earthquakes weren't unheard of in Canterlot, as the city was built into a mountain, but they were few and far between.

Then, all hell broke loose as a massive quake struck the city, causing everything to go everywhere. Ponies everywhere sought shelter as the massive tremor tore apart the streets, making fissures in the cobblestone paths.

It lasted for a little under two minutes, until all was silent once again. As the residents of Canterlot emerged from their homes and hiding places, they came out to a sight of destruction. Buildings all around were damaged, and rubble filled the streets.

It wasn't long before Solar and Lunar Guard chariots began to descend, and the initial panic and chaos was contained by their presence.

However, in the cacophony that ensued, nopony noticed a crack in the base of the Canterlot Plaza Sundial. Below the stone slab that supported the instrument was a sheet of gleaming white metal, inscribed with a strange symbol. The symbol glowed green for a few moments, and then faded.

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Later, as Princesses Celestia and Luna began their survey of the damage, the Solar Princess used her magic to lift a portion of a shop out from under itself. Solar Guardsponies filed in and quickly retrieved the patrons who were trapped inside.

"What a mess." Princess Luna said, kicking a rock aside. "We haven't had an earthquake here in Canterlot for hundreds of years."

"But they can always happen, sister." Celestia replied. "I am glad that so far, nopony was hurt."

"Indeed." Luna said. "Should we prepare for an aftershock?"

"Maybe." Celestia said as the two of them and their retinue entered the plaza. "Though it is curious why one has not occured yet."

As they walked past the base of the sundial, Luna stumbled and fell over. As her sister helped her up, Luna saw what had made her trip.

"Sister?" she asked. "Why is there metal right here?"

"I don't know." Celestia said. "It's not a sewer pipe, that's for certain."

As they stared at the metal sheet, the symbol glowed three times again before fading once more.

"And I don't think our sewers do that." Luna said.

"They certainly don't." Celestia said. As she reached down and touched the symbol, there was a sudden shift in the terrain beneath them. Then, green lights formed around the plaza, spiraling around each other.

As Celestia and Luna watched along with their awestruck retinue, the plaza grounds transformed into a spiral staircase, leading underground.

"Stay here." Celestia ordered her Guards. "My sister and I will investigate this...turn of events."

The Guards looked at each other, uncertain of the command, but they heeded it nonetheless. As Celestia and Luna descended the stairs, the sun and later their magic illuminating their steps, they both shuddered as if it was winter.

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After a few minutes of descending, the two Alicorns found themselves inside a hallway adorned with white, carved metal. As they passed, they realized the carvings were laced together seamlessly, like one giant tapestry along the wall.

"Who could've done this?" Luna asked, tracing her hoof along the wall carvings.

"I think the better question is where did all this come from?" Celestia replied. "None of this is Equestrian in origin, I'm certain of that."

"A brilliant deduction." Luna rolled her eyes. "I could've guessed that about ten minutes ago, sister."

Celestia rolled her own eyes at her sister's remark while they progressed forward. Then, they reached a sealed door.

"Well, shall we turn back?" Luna asked.

"Not yet. Sometimes when you see a door, you knock." Celestia said as she rapped her hoof against it. The door soundlessly opened upwards, revealing a massive cylindrical chamber. Tubes full of magma lined the walls, and at the middle of the chamber was an altar of some kind. As the two sisters approached, it showed a symbol, which to the sisters seemed like an orb with two bull's horns.

"Well, here goes." Luna said, tapping it. The orb faded, and a bright green light appeared in front of them. As the sisters shielded their eyes, a voice spoke. It reminded Celestia of a wise yet old stallion with a gentle yet firm voice.

"Who are you, and what are you doing in this Control Room?"

"A Control Room for what?" Celestia asked. "Identify yourself!"

"I am 3116 Astute Sigil, the Forerunner Monitor of Shield World Tranquility." the voice replied. "You are in the Control Room of this Installation. I will ask again who you are."

"I am Princess Celestia, Ruler of the Sun." Celestia said. "My Sister is Princess Luna, Ruler of the Moon. We come in peace, Astute Sigil."

There was silence throughout the room. Then, Sigil spoke again.

"Understood. Forgive my initial hostility."

The green light faded, and the two sisters got their first look at the Monitor. It was orb-shaped, with a single green eye. Carvings and engravings lined his body, and as it approached them, Luna raised an eyebrow.

"What are you doing here, Astute Sigil?" she asked.

"I could ask you the same thing." Sigil replied. "This installation has been active for quite some time. I have no records in my database of a species like your own. But I digress. Come, I must enlighten you."

"Enlighten us about what?" Celestia requested.

"Enlighten you about my creators, the Forerunners." Sigil said. "This way."

As the two sisters and Sigil were floated into the air by a gravity lift, Sigil gave a few artificial chuckles at the sister's surprised reactions.

"What is this contraption?" Luna asked, spinning around.

"An artificial gravity lift." Sigil said. "One of many Forerunner creations that I currently have archived in my database."

As they floated to a stop in the upper control room, Celestia and Luna stepped forward to face the Monitor.

"What can you tell us of these Forerunners?" Celestia asked. "We wish to know everything you can tell us."

"As you wish." Sigil said. "My story begins countless centuries ago, in the Ecumene of the Forerunners that spanned the stars..."

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Author's Note

Hope you enjoyed!