As soon as River left the party, she felt intensely relieved. Now she could talk to the Doctor the way she wanted to. "Okay, Sweetie, first things first: where, when and what am I?"
"Always to the point, River Song!" he laughed, cantering a little bit. He must've been here a while, already having developed a very horse-like way of expressing himself. "We are in Equestria, though don't ask me the galaxy or universe identification, because… well I'll get to that." His voice had been rising in anger, but it sounded as though it had been struck down. River wondered if the same little voice was chiding him in his head.
"It's year 1000 of the Sun as they call it here, which translates to the 1,576th year that Celestia has ruled over Equestria." He tilted his head at River who looked at his questioningly. "Once again, I'll explain. And you are, as you have no doubt guessed, an equine. A rather odd sort, though. Very… human."
River studied the scenery; the houses and benches could've easily been from Earth if it wasn't for the overly cheerful color scheme. Very human indeed. Her eyes grazed over the scenery and landed on the Doctor. He was watching her with delight in his eyes. Maybe it's not getting out that will be the issue, River thought, maybe it will be convincing him to leave.
"Doctor!" came a call from across the town square. The pair looked up to see Ditzy heading towards them. River made an impatient noise. She finally had a moment alone with her love, and it was spoiled by the interrupting, wall-eyed… No, the Doctor liked Ditzy and so should River. Stupid voice.
"Before it's too late—" River started, but the Doctor was already greeting the pegasus.
"Hello Miss Doo, everything alright?"
"I noticed you were gone, and I thought…" started the pony. Amazing. Even in a new universe companions were terrified of losing the Doctor. River realized maybe this Ditzy was more perceptive than she thought.
"No, I wouldn't leave without saying goodbye." The Doctor smiled his reassuring smile, and Ditzy couldn't help but return it, albeit hers was with a blush. Quickly looking away, the Doctor turned to River "Ditzella Doo, this is River Song, my… er… well…" he cocked his head slightly. It was always difficult explaining their relationship.
"Wife?" River offered. The Doctor nodded, and Ditzy's eyes widened considerably, even focusing fully on River momentarily. She wasn't looking at River with full love in her heart, but she certainly wasn't sizing her up. The moment was gone, and Ditzy's eyes went haywire again.
"So you're like the Doctor?"
Before River could ask what she meant, the Doctor interjected. "Not exactly, but yes, it's on the same page. Think of it like the difference between unicorns and pegasi." He paused for a second and put a hoof to his mouth, thinking. "Except it's nothing like that."
Suddenly, River understood what he meant. "She knows?" she mouthed to the Doctor, who nodded. River's eyes widened. This pegasus knew the Doctor wasn't originally a pony. Impressive.
Luckily Ditzy seemed oblivious to this whole exchange. "So is she here to help with the TARDIE?"
"TARDIS," River corrected. Ditzy really lived up to her name. The voice tisked at River. River ignored it.
The Doctor laughed. "Well, actually, it's the TARDIE right now. Time and Relative Dimension in Equestria. I can't get it to go anywhere else but on this planet, and not even very far." He stamped a hoof on the ground impatiently, then immediately widened his eyes and gaped at River.
"I've still not told you!"
"Told me what, sweetie?"
"About the… well… I haven't thought of a word for it yet. But you know how you can't be the good old aggressive, vicious, sarcastic River I know and love?"
"You're such a romantic."
The Doctor smiled. "Only for you, sweetie." He leaned forward as if to kiss her, but saw Ditzy out of the corner of his eye and cleared his throat instead.
"Anyway, it's because of the thing I haven't quite named yet. Actually, I don't know much about it other than it is very nice, and it wants you to be very nice as well."
"That's right, I do," said the voice.
Everyone froze. They had all heard that. Ditzy's eyes were wide and focused ahead, right behind the Doctor and River. Slowly the two turned to see the speaker.
The Doctor gasped and kneeled, while River stood awestruck. In front of her stood a pure white unicorn with wings, about twice as tall as River herself. She wore a crown and carried herself in such a way that clearly spoke of royal blood. But that wasn't what amazed River. The alicorn's hair was a pink, blue, and green pastel masterpiece, and most impressively it was moving all on its own, flowing as though a breeze or water was ruffling it.
"Who are you?" River heard herself asking, still a bit stunned. Ditzy made a noise behind her, something of disbelief or pain. The taller pony smiled slightly.
"I'm Princess Celestia. And I need your help, Time Lord and Lady."