“W-What's happening?” Twilight whispered, as she watched her other self continue to sob in the middle of the aisle. As the shock of her sudden appearance began to wear off, she noted the condition of her doppelganger, who was covered head to hoof in dozens of small cuts and bruises and was favoring her left hind leg. Interestingly, this other Twilight was still a unicorn, thus lacking the wings indicating her ascension.
Quickly shaking her head, Celestia waved a hoof at the guards and they began ushering the crowd out of the room. Soon the only ones left were the princesses, Nyx, Clockwork, Twilight and her friends. Once the doors to the room were shut, Celestia went and knelt beside Other-Twilight. She draped a wing over her like her other self had done, simply holding her until her crying died down to nothing more than a whimper.
“Why would she do this? I could have done something. I could have figured out a solution. We could have defeated the Tide somehow.” The lavender unicorn looked up at the princess, her face stained with her tears. Celestia hugged her gently as the rest of the remaining ponies quietly approached them.
“What happened?” Princess Twilight asked, sitting in front of her counterpart. Part of her still felt disbelief at the idea of parallel worlds, and yet the evidence was sitting right in front of her. She would have liked to think that it was a trick, a Changeling scheme or one of Discord's pranks, but she could feel in her very being that the pony wrapped by Celestia's wing was herself from a different reality.
Other-Twilight took a shaky breath as she looked at the purple alicorn. She wore an expression of disbelief that settled into acceptance as she came to the same conclusion. Wiping her face with a hoof, she took a few more breaths before she began speaking.
“I was in the Whitetail Woods doing more research on the local Changeling hive when suddenly we felt a tremor. Thinking it was an earthquake they evacuated the hive just in case the cave collapsed. When we got outside we found out that a meteorite had landed by the edge of the woods. Some of us went in for a closer look and we saw it. It was big, about four times the size of Celestia, and it was covered in this black ooze.
“Then all of a sudden the ooze started spreading out. One of the Changelings poked it with a stick and it just dissolved. We got out of there as fast as we could and alerted Queen Polistae. She went to look at it herself and it was already spread out over a mile, and it looked like a big flat lake of oil. She tried to contain it with magic but there was too much of it. We tried to wall it in but it ate right through it. I sent a letter to the Princess to tell her about this problem and by that time it almost reached Ponyville.
“That was when it got worse. There were these...creatures that started coming out of the ooze. A lot of them looked like ponies, earth ponies and unicorns and pegasi and even a couple alicorns, and there were some that walked on two legs. They walked out of the ooze and headed toward the town, and they didn't respond when we tried to talk to them. They started grabbing ponies and dragging them back to the lake of ooze, and then they'd pull them under. It was horrible. We tried to get everypony out of the town toward the farm, but the creatures would just start chasing us.
“We tried to use the Elements of Harmony, but it only pushed back the lake a dozen yards before the magic dissipated. It didn't even affect the creatures. The lake stopped growing for a while after we used the Elements and for a moment we thought we had stopped it completely. There weren't even any more creatures coming out of it.
“But in a couple hours it started growing back, faster than ever. We didn't know what to do, so we just ran. We got as many ponies as we could on the train to Canterlot. We looked to our old home, which was now just a big black puddle. We started calling the ooze the Black Tide.
“The Princesses had no idea what to do. They suggested using the Elements again, but this time nothing happened at all. It was like the Tide became immune to them. Then the princesses went out themselves to try to stop it. They gave it everything they had, using the power of the sun, freezing it, pushing it back with shields, everything. They were able to push it back to the original landing site, but they couldn't destroy the core. It was almost as if it was using magic of its own to protect itself.
“The Tide would come back mere days after each attempt to destroy it. And it would be harder to push back every time. After a month, it would reach Canterlot only a single day after pushing it back to the core. The creatures started invading Canterlot in giant waves, and it took everything we had to push them back. We even used the Elements, but they'd be back in a matter of minutes. They started breaking into the palace, and then...and then Celestia brought me here...” Other-Twilight shook her head, her eyes swimming in tears. “Now I have no idea how to get back or how to save Equestria.” She buried her face in her hooves as she fought off more tears.
Princess Twilight bit her lip as she contemplated this story. Something that could dissolve everything it touched as well as have the power to resist the power of the princesses was too frightening to think about. But at least in her own world, they had at least one extra alicorn. If the Tide ever came there, they might stand a better chance. She just hoped that they wouldn't have to find out.
Celestia stood up and gently nuzzled the distraught unicorn until she slowly got to her own hooves, then personally escorted her to the guest rooms of the palace. Princess Luna ran a hoof over her face, suddenly looking very tired. She peeked out of the windows as the setting sun cast long shadows into the room. “I think it would be best if everypony gets some food and some rest. I will visit you in your room later,” she said to Nyx, who was wearing a concerned frown as she looked toward the door where her mother's look-alike had left. Not waiting for a response, Luna strode outside and leapt into the air as she flew towards her tower in preparation for raising the moon.
“Well, I think that's enough excitement for one day,” Rarity sighed, shaking her head. “Nyx dear, would you like any help getting out of your dress?” She looked at the dark alicorn expectantly, who merely nodded and followed her into the dressing room.
“Ah guess we'd better get out of these dresses too, don't wanna be gettin' food all over `em,” Applejack stated and followed the two mares out. Pinkie Pie, Fluttershy and Rainbow Dash agreed and filed out after her. Now Twilight was left alone in the room, staring out of the window, struggling to deal with what just happened and what she was told. She was jolted out of her thoughts by a metal hoof gently nudging her shoulder, and she turned to Clockwork as it watched her.
“That thing she described...that's what I saw in that world I landed in. The one where I found this.” It held up the cracked amethyst brooch it carried with it.
Twilight shook her head and sighed. “You probably ended up in her world when it landed.” She frowned at the copper unicorn when it shook its head and gave her an odd look.
“She said that the meteorite in her world landed near the edge of the woods. The one that I saw landed near the foot of Canterlot Mountain. They are nowhere near each other. They are different worlds, and the logical conclusion is that that Tide, as she calls it, has been appearing in multiple worlds, and may very well end up in this one as well. You must prepare for it, whether you want to admit it or not.”
Twilight snorted and stomped a hoof. “You're right. But where do we even start? It seems to be impossible to beat, according to her. I can only hope that with an extra alicorn on hoof we might be better at pushing it back.”
Clockwork nodded as the gears in its head began spinning faster. “What if we had more than just one extra?” It turned to look at her, its eyes beginning to glow brighter. “If there are more worlds with other versions of you, there is the possibility that at least one of them is also an alicorn. We could protect this world with their help.”
The lavender alicorn's eyes twinkled as she considered the idea. “And maybe, we could work together to stop the Tide from invading other worlds altogether. It seems that other Twilight seems to be as smart as me, so if we combine our minds we could make the problem so much easier.” She smiled and put a hoof on the clockwork pony's shoulder. “We can do this. We can defeat this Black Tide.”
“But how do we get the other Twilight Sparkles to help?” Twilight jumped as Nyx spoke suddenly, approaching them from the dressing room. “Does the Princess even know how to open doorways into other worlds like that other Celestia? And how do we convince the other Twilights to help us solve this problem?”
“It is likely that Celestia had the ability to open these doorways. Many things are similar between the worlds, apparently. As to convincing the other Twilights, we will just have trust that they will listen to themselves.” Clockwork flicked his tail as he thought, the chains rustling against each other. “But we have time to work on this dilemma tomorrow, I would think. It's late, and the moon has risen. And your bodies need food.” The two alicorns blushed as their stomachs rumbled at the mention of food. “I will talk to you later. Good night.” At that, Clockwork turned and left to the guest rooms, leaving mother and daughter to go seek out a late meal.