It was one of my more interesting conversations with the Princess.

The Court of the Day had closed early, my inquisitors from the Equestrian scientific community had run dry of questions to ask and tests to perform, and Celestia and I found ourselves enjoying the luxury of a rare empty hour. We were sitting in one of her gardens, admiring her golden apple tree while I related the mythical legend of Eris, Paris, and Troy.  (She found our mythological goddess of discord to be far more subtle than her own Chaotic nemesis.)  As the topic wandered, I chanced upon a thought, a question I had not had opportunity to ask prior. "Tell me, your Highness," I said, "From the other side of the screen, it seemed very odd indeed that after your sister's liberation from Nightmare Moon she failed to appear anywhere for well over a year. Tell me, was there some difficulty in acclimating her to the new era....?"

Celestia, to my surprise, looked distressed at the question. She shifted uncomfortably on her reclining bench, her eyes darting away from me. "There was.... a little," she said. "But that was not our chiefest concern. You may have not noted it but there has been relatively little change in Equestria over the last thousand years--- at least when compared to your own world or country."

"From the ox and cart to the space shuttle, yes," I muttered. "Considering the mayhem we went through along the way I think humans could have happily coped with far fewer 'interesting times.' " Celestia laughed a bit nervously.  "But I digress. you were saying?"

"As I was saying... her adjustment to the changes over the millenium were the least of anyone's concerns," she continued. She lowered her voice. "Please do not bandy this about--- it would cause.... distress among the ponies outside the castle. But the reason for her isolation for so long was... medical in reason."

"Luna was sick?"

Celestia bit her lip. "Perhaps it would be easier to show you," she said. Morphic light spilled from her horn, forming a silvery disc in the air before us. It solidified into a glowing mirror.... no, a window. The sun in the reflection was in a different place in the sky, and the garden was in bloom with flowers from a different season. The flowerbeds were full of late summer blossoms.

And Luna was lying on her back in one of them, smashed completely off her plot.

It was the "little" Luna, with the pale, short mane; it must have been shortly after she had been freed. She was lying on her back in the middle of a half destroyed flowerbed, bicycling her hooves in the air and giggling like she'd lost her mind. "Luna!" Celestia's voice came from the mirror. The view drew closer to the potted princess, looking down on her; I realized we were seeing this memory from Celestia's perspective. "Luna, are you all right? What in heaven's name are you doing?"

"Hiiiiii, Tiiia," Luna drawled up at her sister. "'M just smellin' th' flowers." She gathered a bunch in her hooves and crammed her nose into them, inhaling deeply. "Mmmmm, so good....."

Celestia's memory-voice was a mix of annoyance and concern. "Luna? Are you drunk?"

"Naaaaaaah. Hey, Tia.... I was just thinkin'.... about these flowers? They, they, they....... " Luna paused and frowned. "Oh yeah.... I was thinkin' how they're flowers, Right? And they don't know they're flowers..... but they're still all happy with that.... "

Yes. She was smashed, snockered, blasted, fried, bombed right out of her gourd.

The mirror faded and vanished in a cloud of mist. "that was only the first time," Celestia said. "Time and time again, I or some member of the palace staff would find her in this state. Euphoric, barely able to stand, insensate, even.... "

"...She.... took to the bottle?" I hazarded. "Or to something more, ah, herbal?"

Celestia seemed to understand what I was driving at. She shook her head. "That's the first thing the physicians and I thought," she said. "We watched her carefully for days, weeks. She never took more than a glass or two of wine at meals, she had no secret stashes or binges, never imbibed in any exotic plants... her physicians confirmed there was nothing in her bloodstream...She of course insisted that she was not indulging in anything...."

"We obviously kept it quiet; it would hardly do to have it known that Equestria's long lost Princess spent most of her time blitzed." Celestia rolled her eyes. "After a while she seemed to get better. But even now she has these fits. They seem to strike without warning, generally whenever she's doing something idle.... She'll be eating a bite of dessert, or be walking among the flowers, or step out into a patch of sunshine, or admiring a painting. And she'll keel over like a felled tree.

"I'm so worried, Arthur. What if there's something seriously wrong with her? The doctors have found nothing-- no sicknesses, no injuries to her brain, but--- it keeps happening. Last week the maids found her rolling around in the linen, rhapsodizing about how soft the sheets were and how nice the smell was.... what, what's so funny?"

Despite myself I was grinning behind my hand. "I, ah, think I might know what it is," I said, starting to chuckle. "Tell me, do your researchers know anything about sensory deprivation?"

She said nothing, but I guessed 'no' from her nonplussed look. Grinning, I proceeded to explain. "Back on Earth, scientists would do lots of things to study-- well, the mind, the brain, how they work and all. How people responded to stimulus, that sort of thing. One of the things they developed was sensory deprivation studies. Basically the subject would be placed in a darkened tank half full of warm, saline water. Earplugs and eye coverings provided as well-- isolating them from all sensory input, or as much as possible: no sight, no sound, no smell, no sense of touch.... then they'd study what their reactions were. The results were.... interesting to say the least.

"One of the reported side effects of sensory deprivation was that, after a couple of hours, when the subject came out of the tank, their senses were temporarily enhanced. Colors, textures, smells, everything was incredibly intense, to the point of being intoxicating."

"Now you're both immortal beings, so I can guess you respond to certain things differently. That probably protected her from the detrimental effects. But all the same, she just spent a thousand years trapped in the moon, with little or no sensory stimuli. And I'm guessing the Friendship Beam from the elements of harmony probably purged her of any negative effects of her isolation. Afterwards, though...." I shrugged.

"Are you saying that my little Luna is getting--?"

"Drunk on life, yes," I chuckled. "The smell of a rose, an involving bit of music, an attractive painting.... my word, the taste of chocolate must have been like a bomb going off in her pleasure centers."

"Good heavens." Celestia stared off into space. "that makes perfect sense, really. It explains everything." relief washed across her face. " That takes such a load off my mind. I've been having visions of bizarre curses or some horrible sort of brain tumor---" she laughed in relief.  "I hope it eventually wears off though..."

"Eventually," I agreed. "No telling how long though. She was isolated for ten centuries, it's bound to be a few years before it stops completely...."

Celestia suddenly pricked up her ears. "Do you hear that?" she asked.

"What?" I shrugged.

The royal ears swiveled. "....Singing," she said, bemused.

Intrigued, Celestia got to her feet and followed her pricked ears; I lumbered to my feet and followed. We wandered our way to the other end of the garden. As we came to a secluded nook the singing became quite clear. I spotted dark blue hooves waving above the daffodils.

"Lu-na in the sky-y-y with di-a-mondssss....."

It was Luna. She was lying on her back in a shaded little grotto. Her cheeks were flushed, her crown was askew and she had an enormous milkshake glass, complete with swirly straw, balanced on her chest. "OH HELLO, TIA AND ARTY!" She said, blowing our hair back slightly. "May I call you Arty? 'Course I can, I'm the princess...! Anyway, HELLO!"

"Luna, are you--" Celestia began. Luna waved her off. "Ohhh, fine, fine fine fine. I'm fine. Say, dost thou know what this is?" She pointed to the ice cream and whipped topping confection balanced on her chest. "It'sa strawberry malted! One of the kitchen staff made it for me. We decree he shall be knighted immediately!" Luna giggled, snorting a bit. "You should try thish, Tia, issa best thing inna yuuuuuniverse mmmmmmm..." she took a long drink from the loopy straw before starting to sing again.

"....You know, I think I actually envy her at the moment," Celestia said with a sigh.