Nightmare Moon is pacing. And thinking. And worrying. Pace, think, worry, pace, think, worry. She's already dismissed the (trembling, terrified) castle servants. Equestria is starving. The night has lasted for 83 hours now. Without the sun's warmth and light, crops are dying. The ground is cooling, bringing an unnatural winter. If she can't figure out how to raise the sun, she'll be the only thing left alive on this half of the planet.
But only Celestia can raise the sun.
And Celestia is dead.
Nightmare Moon killed her. She doesn't know if she meant to. Doesn't know if she wanted to. Right now, she mostly wants to throw up. It doesn't matter anyway. She can raise and lower the moon, can make it do loop-de-loops, can make it seem to bounce along the horizon, but she can't so much as touch the sun. She's tried. She spent fifteen minutes unconscious and an hour nursing the migraine from magical backlash before she stood up and forced herself to cast an anesthetic spell so she could keep thinking.
Nightmare Moon paces. And thinks. And runs into a table. Startled, she looks up and discovers that she's no longer in the corridor, and in fact that the room she's now in looks like nothing so much as a tavern, albeit an eerily silent one. There's only one other patron, a strange gangly thing that pulls up short to avoid running into her. "Hello," it says. "You look confused. Let me be conveniently very helpful. This is Milliways. Time is stopped in your world until you leave." Nightmare Moon blinks, but the thing keeps going. "It's some kind of dimensional nexus. You can leave whenever you want but if you let the door close no promises you'll make it back here. Don't try to fuck stuff up or Security will hand you your ass. Bar can make stuff, as long as it's not alive, not magic, and fits on the counter. First drink is free, you look like you need one. Cheers." And it's gone.
Well. That's... huh.
A wave of relief nearly swamps her, leaving her surprised by the force of it. Time. She has time, time to figure out what to do, time that won't be wasted as long as she doesn't leave. She walks to the bar. "Milliways? Do you have access to printed materials?"
A napkin appears on the counter in front of her. Call me Bar, but yes. Could I get you a drink first?
As much as Nightmare Moon would love something alcoholic enough to kill a normal pony, this isn't the time. Or... wasn't she just thinking she had all the time she needed, now? "Can you make moonshine?" she asks, curious despite the situation.
I can make almost anything, Bar replies, and sure enough, next to the second napkin a flask appears of the star-brewed stuff Lu... Nightmare Moon made one night several hundred years ago (and then banned the following morning). She uncorks it, takes a shot, then gags after choking it down. "Stars, that's vile." She takes another gulp. Okay. Time to do some research.