I followed Miss Sparkle into the library, my two loyal guards taking up posts outside of the door in case I tried to make a break for it. Honestly, did they think me dumb enough to try such a blatant exit? One of the upstairs windows perhaps, or out through the kitchen, but not the front door, "Twilight, I-"
She cut me off by raising a hoof in the air, "Not right now, Alto. I don't want to hear it. I just want to get this interview over so we can send this changeling on its way home or to the gallows. It won't talk to me, so maybe it will talk to you."
I sighed, heartbroken that she would use the word gallows, "Very well, where is it?"
"In here," she said, opening the door to a stairwell that descended into a laboratory. There were devices for recording information, chemist gear, and what looked like a cauldron off in one corner. Once we reached bottom, she knocked on the cell bars that were surrounding my former cellmate, "Alto is here, will you talk with him?"
The creature nodded as I approached, "You wear another binder? We thought you would be touted as a hero for what you have done. We are saddened."
"Please... stop saying we, you're reminding me of the borg."
"Borg? Sounds Wheatish."
I tilted my head, unsure where the word had come from myself, before turning back to the Changeling, "If you can, please use singular pronouns?" it nodded, "and do you have a name and ... well, a gender? It's awkward calling you 'it' all the time."
"My designation is Delta-365. I'm female," she said after a few moments of silence. Her manner was beginning to soften as well, at least, assuming their mannerisms were similar to the ones ponies had.
"Can I call you Delta?" she nodded, "Okay, well, Twilight has some questions, and will be using a truth-sight spell, so... Please answer her, otherwise we're both bucked harder than one of Applejack's trees."
"I've been through this a few times before. Ask your questions, Miss Sparkle, I won't lie to you."
"Well, if you do, I'll know."
I excused myself briefly to use the restroom upstairs and found that the pair of guards that had escorted us to the library were currently patrolling the yard. I waved a hoof as I maneuvered myself to use the toilet and was glad that the window itself was high enough that they could see nothing below my neck. Once I was finished with my business, I returned downstairs and found Twilight deeply engrossed in conversation with Delta.
"So a Changeling is given a designation based on the order they hatch and which egg cluster they are part of? Fascinating! I'll have to add that to my research notes. Now, you said you were initially sent to Ponyville to contact somepony, who was it?"
"I was sent to contact the stallion now known as Alto."
"Me? Why?" I asked, honestly dumbfounded.
"I suppose the proper way of saying is not that I was sent, it is that I came of my own accord after Queen Chrysalis was deposed by Princess Pupitea."
"You... what?" we both asked asked at the same time.
She sighed and stood up slowly, making no threatening motions, "Miss Sparkle, if I may use my shapechanging abilities once? I have heard of Alto's memory problems since my arrival and before my capture and... I believe I can help him."
"You may," the unicorn next to me said as I continued to try and process how I could have ever known a Changeling. Twilight briefly removed the binder from Delta and there was a flash of green fire. In the future, should you ever be around Changelings as they are changing shape, do not stare directly at them, it can blind you, as it did to me for a brief time.
It took me several moments to blink the basement lab back into sight, though the colors were still muted. My first vision was of Twilight looking shocked at something, so I turned to see what she was looking at.
My own mind very nearly exploded as I beheld the vision in front of me. She was tall, nearly as tall as Celestia herself, clad in soft home-spun silks of myriad colors. Her mane fell gracefully down her back, and was a vibrant red. The eyes that bored into my own were a piercing green, glittering like emeralds in the sun. Smiling, she took a single step forward and plucked the binder out of the air and placed it on one of her fingers as if it were a ring.
"You're..." I began, unable to choose between beautiful, stunning, and radiant.
"A human..." Twilight finished for me as she got over her shock.
"A what? What's a human?" I asked, confused.
Delta kneeled down, placing her face next to the bars of her cage, "Come here, Alto."
I was unable to resist, and Twilight prepared herself if I needed rescue. I did not, as the human pulled my face to hers and kissed me. I melted against her lips as I felt my body tingle in pleasure, then the rush of knowledge hit me like a sledgehammer, my eyes went wide and I smiled, breaking the kiss before looking over at Twilight.
"I remember..." I whispered before I passed out again. I wish I could stop doing that.