"Not mine, or we'd have heard of him. At least I assume so, I haven't heard of anyone else with that kind of power who doesn't flaunt it... though I suppose I wouldn't have, would I...? Never mind. I shall ask them later."

She raises an eyebrow. "I'm aware of why alicorns are considered good in my world, but why should they be so in yours?"

Here you are, says Bar, presenting a ballpoint pen along with the napkin.

"My tutor once rode a winged Horse to rescue his mother from Jadis, and the winged horse is also the emblem of the part of the British Army a friend has advised me to join once I'm old enough to enlist. And God in normally very subtle- we went hundreds of years with most people not knowing He existed. Anyway."

He draws a map and explains to Nightmare how to find his brother and sisters, who are in various boarding schools scattered around the southern half of a large island.

"Very well. I should note that most pegasi cannot do a fraction of what I can--winged ponies or no. An alicorn is greater than the sum of her parts. And technically horses are from Meshippotamia, which is closer to Zebrica than Equestria. Who is Jadis?"

She studies the map as he goes over it, then repeats the key points to confirm them. "How am I to find your siblings? From your descriptions of the places I take it they're not used to entertaining royalty, and I would rather a minimum of fuss."

"Jadis was an evil witch who ruled Narnia tyrannically and caused the sorcerous winter. My siblings' names are Susan, Edmund and Lucy Pevensie, people will be able to point you to them. I'm afraid that the sight of a winged unicorn in England may inevitably cause a fuss."

"Sounds like a Windigo to me. Strange, the similarities between worlds. Susan, Edmund, Lucy. Are their mane and coat colors similar to yours? Well--mane, anyway, I suppose you don't have a coat." She pauses, then looks a little sheepish. "Ah--if they ask who sent me, what should I say? I don't believe there have been any formal introductions between us.

"I had planned to fly invisibly, assuming the spell works. If it's night I may not need it anyway. This tutor of yours--shall I find him as well? And how am I to return to Milliways once our allies have been gathered?"

"Oh- yes, returning to Milliways to Earth might be a problem. So perhaps we should begin with evacuating your world here, if you expect that door to be more reliable."

"Unfortunately, I do not, and I am loathe to restart time without a concrete plan. Bar, is there some token I may carry to guarantee safe passage between worlds?"

No. However, you may hold the door open as long as you like.

"There you have it," Nightmare says, turning back to the human. "Unless there is some immediate crisis that you have failed to mention."

"Holding the door will keep the passage open, then?", Peter asks the bar. "Does that apply to the door to England as well?"

Yes to both questions, so long as the person who opens the door initially is a native of that world.

Nightmare frowns. "Time will flow normally in England while the door is open, yes? What about Equestria?"

Time will remain paused so long as you intend and are able to return here.

The alicorn rounds on Peter, turquoise eyes blazing with some unholy fire. "Don't. Let. Go."

"On my name and my honour I will not let go of the door until you return here."

(to the bar) "Thank you"

(To Nightmare again) "Susan and Lucy have hair about the same color as mine, Edmund's is lighter. And my name is Peter Pevensie. My tutor..."

he gives directions to an office in a university, and directs Nightmare to ask after Professor Digory Kirke.

She nods to him seriously. With her horn, it comes off vaguely as though she's knighting him, though she doesn't seem to notice the cultural echo. "I shall away, then. After you, Peter Pevensie."

Peter holds the door for Nightmare. It leads to a school corridor.

She nods to him again, looks up and down the corridor, and lights her horn. Shortly, she seems to shimmer out of existence. 

"Excellent," says Nightmare Moon's voice, from somewhere in the middle of the corridor. "I shall return with all haste." Hoofbeats mark her movement to the end of the hall--and then back.

"Er," says the lunar princess, sounding rather sheepish. "Which way is out?"

"Left to the end will get you to the stairwell. Then turn right into the ground floor and you'll find the foyer on your right."

"Thank you," says Nightmare, and leaves--in the correct direction, this time. On her way outside, she passes a number of other humans, who all look worryingly similar to Peter. She hopes they can tell each other apart, or at least don't all wear the same clothes all the time. It's going to be a very long trip, otherwise.

When she reaches a stone clearing, she leaps into the air, glad that flying also seems to work normally in this world. With a quick spell to determine the cardinal directions, she adjusts course for the university when she can find this Kirke, figuring that it will be easier to convince Peter's siblings to join her if someone they trust is already on her side.

It doesn't take her long to get there, despite keeping a low altitude so as not to lose her way above the cloud cover. Getting there is one thing, though; getting inside is another matter entirely.

"This is worse than the School for Gifted Unicorns," she grumbles, after having possibly gone in a circle. She remembers Peter's directions perfectly, thank you alicorn brain, but all the buildings look alike and she has a growing suspicion that she didn't start in the right place. Eventually she sighs, drops her invisibility, and wanders back to where she last saw a human.

"Excuse me," sir? madam? whatever-- "would you be so kind as to direct me to the office of Professor Digory Kirke?" Maybe she can bluff her way past all the ceremonial nonsense by just pretending that nothing is out of the ordinary. It's worked before.

People startle and stare at her.

"Um. I believe his office is in the Gibson building. If you go through there you'll come to a lawn and it's across the lawn to your right."

"Thank you," Nightmare Moon says, and takes her leave in the direction the human had pointed. Across the lawn, to the right, and there's a building with a plaque by the door reading something about how, presumably, Gibson gave them enough money to get a building named after her. How nice for everyone involved. She ducks her head to avoid smacking her horn on the doorframe, then, once inside, looks around for a directory of some sort, or maybe a map.

There is not a map evident. There is a desk at which several humans are queuing, and at which a clerk is telling the human at the front of the queue where they can find someone named Professor Lightfoot.

Excellent. Nightmare Moon trots up to the desk, ignoring the line. Royalty does have its perks.

"Do you know where I might find a Professor Kirke? Digory Kirke, if there's more than one."

The clerk doesn't know what to make of the unicorn asking after Professor Kirke. Fortunately, since it isn't in line it is presumably not her problem and she can just continue directing this man to Professor Lightfoot's office.

"If this is how you treat all visiting heads of state no wonder you're at war. I apologize for the interruption, but this is a matter of some urgency. Kindly either tell me where Kirke is or give me something of his so that I may find him myself."

Peoples' surprised expressions become more alarmed, and several of them move their hands in an unfamiliar gesture. The man at the desk, however, anxiously asks the clerk if she might also direct him to Professor Kirke.

"And are you asking that because a black unicorn is making a fuss about it?"

"Um. Yes? I figure he'd have a better idea what to do about her than we do."

"...I suppose so."

the clerk gives the man directions to both professors.

"Was that so hard?" Nightmare Moon unfurls her wings slightly, to make a point of them. "Trust me, I can be so much worse than a mere unicorn."

She looks away suddenly, and snorts. It's a surprisingly horse-like noise and movement, considering the perfectly fluent Equestrian that came before it. She hadn't been lying, though; she really doesn't have time for this. Without a word, she stalks off, following the directions to this Professor Kirke. Hopefully he'll be easier to work with.

The directions lead her to a closed door, at which she knocks. Briskly.

"Come in!"

She does so, using her magic to turn the doorknob rather than fumble at it with her hooves. "You are Professor Digory Kirke? Your presence is required, as is that of your pupils. Make haste, if you would."