Twilight "awoke" to find she was in a desert, not unlike the outskirts of Appleloosa. In fact there was a train engine turnstile some ways in front of them all, with six tracks leading into the distances … all of which were, she noticed, nondescript to the point that wasn't sure the tracks weren't some sort of illusion.
But it didn't have the oppressive feel of her nightmares. Just, an odd sort of disconnect. A part of her mind said this isn't real but all of her senses registered normally. There was not much to smell, but even that sense, she could detect blown dust, and the working of giant steel machines.
She saw her friends all in a line, facing the turnstile. Also, there was the elite guard who had insisted on following the princess into dream, next to an especially radiant princess Celestia. Twilight heard the guard say "But where is the other princess, my liege?"
And then she materialized. In here she was as tall as her elder sister, and her mane nearly as large. She was walking towards Celestia, which meant most ponies present saw her walking to their right. "Celly I have some leads but I want to speak privately." When the elder nodded assent to the junior, Luna turned to the elements, and also Jack, who was, Twilight just realized, in alicorn shape. Luna was augmenting her voice now, although it probably wouldn't have been needed. "Friends, this place at the meeting of tracks is inside my own dream, and I promise I shall maintain it though I be awake, for as princess of the night, dream is also familiar to me.
"Each track here, leads to the dream of an element of harmony. Yourself. I know not what you must find, or how your own mind shall accept you, but you must travel to the most sacred place of your own country, and take the tool, or weapon you find there.
"Natural time is slowed; the rate will vary but an hour here will take roughly ten minutes
in the waking world. You may eat here but you will not need anything. This counts as sleep so you do not need to sleep more while you travel. As you learn to operate the dreaming you will find you can shift reality and this shall be your greatest defense.
"But in the waking world you will need to eat so I will instruct Jack how to anchor your minds to a particular point in the dream world, and every two to three days, you must leave, and awake, and live your lives before returning here.
"I have learned that the interloper must be magically following you, and as only one pony may only follow a single point, or a single dream. I do not believe there are more than one interloper but he or she is strong, and a very fast learner of new attacks.
"Good luck to you all, but I must speak with prince Jack, then I believe we princesses shall leave you to your quest."
Jack had accidentally become a regent by drawing so much magic that no "unicorn" could safely channel it. As his first deliberate spell after he became royalty he made himself an alicorn with obsidian hooves, and the hair starting as black but fading into a shifting, grizzled slate gray, with mane & tail the color of beach sand and wings that nearly glowed they were so white. It made his voice easier to interpret, for which she was grateful and likely not the only pony present who felt that way.
There was a clip-clop of perhaps aluminum shoes as Jack wandered past the assembled ponies to the huddle of alicorns. Since Luna had said she wanted to speak privately Twilight walked the other way to gather her friends. A huddle of mere mares here, demigods there. Twilight giggled slightly.
"And what's so funny, huh?" Applejack was quite tense, but as Twilight recalled AJ's nightmare settings had often been in deserts like this. Twilight tried to ease her fears.
"Just that we look like competing sports teams. Gonna be a short competition if so." Twilight waved her horn at the double sized ponies gathered some distance away. "Anyway I guess we can expect resistance from the interloper as well as ourselves if Luna's announcement was right." She looked at the train, and hoped it either weighed incredibly little, or in the dreaming could pull itself. Applejack was the only source of muscle here and she'd resent pulling everypony everywhere all the time.
Pinkie Pie, naturally, was excited. "Whose dream are we going to first? Twilight do you want to find the dream form of the element of magic? I wonder if it's a big crown thingie or if in here we all get crowns and you have to wear a giant necklace to set you apart? This is kinda cool " Barely pausing for breath, she turned to Rainbow Dash, who was eying Pinkie with more scorn than Twilight thought was normal for the pair. "Dash is this what your dreams were like all dry and wind blown what was scary about that can you tell us Dash" here she started pogo hopping around the huddle. "I think we should go to your country first so we can help you sleep so I don't have to find your cloud and climb up to give you drugs hidden in a cupcake because I hate hiding things from you in fact Dash I didn't I told you I was drugging"
Here Rainbow Dash grabbed Pinkie's muzzle as she bounced past, and rather abruptly twisted the jump so the pink party pony would land on her side. "Pinkie." Dash took a deep breath, eyes closed, now open again. "My nightmares involved you torturing me to death repeatedly. We're friends, alright, but every time I see you in here I'm afraid you're going to start hacking my wings off with a bone saw. So pardon me if I don't share your enthusiasm."
There was a collective gasp as Pinkie got back up, now near to tears but afraid to reach out to Rainbow. Dash was stoically staring straight ahead, head lowered and ears looking quite sad; even pathetic.
Twilight spoke into the shocked silence, hoping her own experience would help Dash get through this coming quest. "Dash I know what that's like. Some of my bad dreams, well not all of them but some were of princess Celestia going power mad and killing ponies wholesale. I had to watch, powerless, as she reduced Ponyville to ash, melting or crushing or simply dismembering everypony I know." Twilight looked over her shoulder at her teacher, who was talking just now, primarily it looked like to her sister Luna. "But Celestia not only wouldn't do that, she didn't." Eye contact now with those reddish purple irises. "Neither did Pinkie. We're here to fix that, alright?" Looking quickly at every one of the ponies assembled she continued. "Somehow a thing has found a way to drive us apart but we're not going to let it. I don't know what this will look like, but we need to keep faith that we're all the ponies we love and know outside, in the waking world."
Heads nodding assent, and Dash managed to pull herself out of her deep funk far enough to playfully poke Pinkie in the shoulder, although he face didn't look like she was ready to be this close to the party pony yet.
Pinkie's thoughts on that whole affair left a different taste in her mouth obviously, because she launched herself at Dash and hugged the pegasus' neck tightly as she spoke promises to defend her bestest friend against any and all fake not-party ponies that might dare to wear the color pink.