Waiting patiently, Bucky watched as Luna inspected the vault entrance on the floor of his tower. He watched her expressions, the flutter of her wings, the way her ears moved as she studied the entrance. He watched her lips moue, and watched as she gave a sturdy knock with one silver shod front hoof.

“This is extraordinary work. A door made of solid glass, yet more secure than a door made of regular steel. I am impressed,” Luna stated, lifting her head and looking at Bucky.

“I wouldn’t try testing it,” Bucky warned, his voice insistent. “I’ve placed a spell mirror on it. It could be… dangerous.”

“Hmm, I didn’t detect that,” Luna said, her gaze dropping down to the circular glass door in the floor. She tapped it again and then looked at Bucky. “I suppose that is the point though. Undetectable enchantments. You’ve become quite powerful.”

Shrugging, Bucky made a dismissive gesture with his stump. “I am still lousy with personal defense. Witching Hour and Lyra tease me constantly.”

“I am satisfied that the orb is safe and other curious ponies will be kept away from it,” Luna said.

“Wonderful. So, what is the lesson for tonight?” Bucky inquired.

“Tonight, we travel. Sentinel too. There is something there I wish for you to see,” Luna answered. “My Myrmidons returned from the south with a few things most unusual in their possession. What they brought back concerns me Buckminster. I am afraid, and I am not one that scares easily.”

“Oh bother,” Bucky muttered.

“Sentinel, stop squirming. It is unbecoming,” Luna patiently instructed.

Saying nothing, Sentinel tried to sit still. He looked around at the room made of black volcanic stone. It was hot, stuffy, and the air smelled like Rising Star, somewhat foul with a hint of rotten eggs. There was a massive black slab of stone that served as a table. There were no windows in this room, and Sentinel desperately wanted some fresh air.

“Hey, that’s not fair, I’m squirming too but you scolded Sentinel,” Bucky grumbled.

“Buckminster, stop squirming, your Mistress wills it,” Luna commanded.

“Yes Mistress,” Bucky replied in a low voice, giving Luna a petulant sour look. “What are we waiting on exactly?”

“That is what I want to know,” Luna said impatiently.

“So where are we exactly?” Bucky asked.

“Hidden Hollow Fortress. It is not on any map. It is a recent construction, we are still excavating new levels actually, located under Rambling Rock Ridge. We currently do not have a surface entrance larger than a small berry, which is why I had to shadow portal us down here,” Luna answered.

“Fascinating,” Bucky remarked.

“So a top secret location,” Sentinel stated.

“Indeed,” Luna responded. “A research facility and a base of operations for my agents. Eventually this will be one of the command centers for the Black Cloaks. Your demon orb was studied here Buckminster. Some of my best researchers were impressed. It bears the magical residue of time travel.”

“I might have had to go back in time and help myself out to make it,” Bucky replied in a noncommittal manner. He scratched himself with a hoof, not caring about the look that Luna was giving him. “It is far too hot in here,” Bucky complained. “I’m tempted to cool this place off.”

“Far below us is a number of geothermal caverns filled with boiling hot springs. We will be using steam to power this facility and to operate the lifts. And everything else as well. We have one steam turbine already running and dozens more are going to be constructed. This is why we will always need unicorns. Secret skunkworks and hidden Crown projects,” Luna said, offering some explanation about the heat.

“Skunks. Not food,” Sentinel grumbled.

“Of course they’re not food,” Luna responded, turning one eye upon Sentinel and raising her eyebrow. For a moment, she held her serious mien, and then her face slowly broke into a wide grin. “You learned that the hard way.”

“Sure did,” Sentinel growled. “I hate skunks. Maybe I’ll still eat one out of spite.”

A unicorn trotted into the room, looking apologetic. “We’re sorry, the lift went down for a while and ventilation went down as well for the observation lab. There was barely any breathable air for a time. We are ready to display the exhibit.”

The observation lab was more black stone. A vast long expanse, scarcely furnished, with study cubicles and glass dividers that created workspaces. There were no creatures here yet, but there would be, or so Bucky guessed as he looked around at the various pens and containment units being constructed. Copper pipes ran along the ceiling and large steel ducts ran along where the ceiling met the wall on Bucky’s left. The air smelled stale and the stench of eggs was much stronger, just as Bucky imagined Dinky and Piña’s bedroom must be smelling right about now. Something in the distance went clang in a regular rhythmic pattern.

Ahead, there were bright lights, electric lights, all of them offering a soft yellow glow. As they drew closer, the lights grew brighter, and Bucky could see an observation cubicle that was completely finished. It currently had a curtain over the window, offering a flair of the dramatic for whatever came next.

Finally, the trio came to the window, standing close, and the unicorn escorting them hurried off into a nook, still looking apologetic and worried, casting fitful neurotic glances at Luna.

“We’ve captured something most interesting,” Luna announced. “There’s been lots of rumours, but this is the confirmation we’ve needed. Have a look.” As she finished speaking, Luna whisked away the curtain to reveal what was behind the window.

Gasping, Bucky found himself staring at a changeling. It didn’t look right. He wasn’t sure why he felt that way, but the creature just seemed off somehow. It was small, black, the carapace looked dull, and the eyes were a cloudy blue colour. It twitched occasionally and then it turned its head slowly towards the window.

“It’s hideous,” Sentinel gasped.

“It’s dead,” Luna stated.

“What?” Bucky cried in alarm.

“Undead changeling. A zombie to use the silly modern parlance. It is quite fascinating really. Shall I begin the lesson?” Luna asked, turning to look at Bucky and Sentinel.

The pair nodded together, Sentinel moving closer to his father until he brushed up against his father’s leg. Bucky sat down upon the floor, easing his haunches down slowly, and then silently urged Sentinel to sit down beside him. Sentinel sat down, pressing against his father’s side, sitting haunch to haunch. He pressed his head into his father’s ribs and peered through the window through narrowed eyes.

“The subject is most curious. Undead. Does not need to consume flesh to fuel animation. Still feeds on love, which is a terrifying prospect. Subject regenerates alarmingly fast in the presence of creatures who love one another. Whole limbs can be regrown in seconds. If we were to drop the magical containment field, the changeling would still be capable of mirroring one of us. This is a repurposed infiltrator. We have disenchanted it quite a bit, but it had spells that would allow for remote viewing, allowing the viewer to see whatever the changeling sees. It is non violent. It has no desire to attack anything at all. What concerns me is that we might have quite a few walking among us right now, acting as spies. Our anti-illusion spells work on regular changelings and we are currently modifying the spells to deal with this new threat. Since it feeds on love, it leaves behind no trace of its passing, no dead bodies, nothing. Detecting them will be difficult and we dare not use necromantic detect undead spells,” Luna explained. When she was done speaking, her horn flared brightly for a moment, and one of the changeling’s legs was torn free. Immediately, a new leg began to form, growing rapidly, and the leg that was torn off rapidly turned into a fine powdery dust.

“This is incredible purpose driven magic,” Bucky whispered, his voice faint and sounding as though he was in shock. He shook his head. “Somepony went through a lot of trouble to create something like this.”

“This is frightening,” Sentinel squeaked.

“It gets better,” Luna stated.

“Do tell,” Bucky acknowledged.

“The creature is female. We have never encountered a female changeling other than Queen Chrysalis before. Before her death, she was fertile. We have encountered plenty of male drones, all made sterile, and this discovery leads our researchers to suggest that changelings of both sexes are born fertile and something happens to sterilise them. We do not know what happens to the females, but here we have one. One of our researchers believes this changeling was hatched from an egg stolen away from Queen Chrysalis, which is only a theory for now. The brain seems far more developed than a standard changeling brain, or maybe that is because it is female. We have chopped off the head of this one several times and slowed down the artificial decay process just long enough to have a chance to get a few glimpses. It lacks the syrupy fluid around the brain that we have discovered in other changelings we have captured. It could be because it is dead, because it is female, or because this creature might not have gone through whatever process might exist to make it a loyal slave to Chrysalis’ whims,” Luna elucidated, lecturing in a rather long winded fashion and in detail.

“So this was a fortunate find,” Sentinel said, lifting his head a little higher to have a look at the changeling, who was now whole of body. “The leg grew back quickly,” he observed.

“There is a lot of love present,” Luna replied. “My love for both of you, the love of a father for his son, the love a son has for his father, there is a veritable feast for a changeling between the three of us.”

“So right now, we could potentially have any number of these things running around, somepony could be watching us, and whatever it is, it is strong enough to challenge the might of the changelings, or at least infiltrate the changelings lair and steal eggs as needed… I say this because I doubt that Chrysalis would willingly give her eggs away, the implications of everything involved here are quite unsettling,” Bucky said, looking away from the window and turning his gaze to Luna. “We have a very dangerous enemy lurking in the shadows. And I suspect it is the mirror travelers.”

“I do as well, and it makes me feel better to hear you say that,” Luna said, turning around completely to face Bucky and Sentinel. “Twilight is reluctant to reveal her feelings, she wants more time to study. She says that the source spell for remote viewing is in the abandoned city of Las Pegasus. I am tempted to send my Myrmidons there in force, but I do not want to risk their safety unless I absolutely have to. Fighting an unknown enemy is risky. Each Myrmidon is many years of investment and losing them is especially painful for me, not just a loss of an asset, but a loss of a friend and a loved one.”

Bucky focused on the bug, studying its twitchy movements, watching as it paced slowly back and forth in front of the window. He rose up on three legs, hobbled over to the window, and looked in, his snoot touching the glass. “What if they are like us but they just look bad on the outside?” he asked in a pained voice. “Every day I look at my colt, I look at Sentinel and think about how different he looks from other ponies and I wonder if there are those narrow minded souls who question if he is even a pony at all. I pity those who hate and fear him just because he is different. And then I am forced to examine my own values because of what I see when I look at a changeling. What if they really are like us? What if Chrysalis is doing something to them that takes away their free will and makes them slaves? And what if nopony cares about their plight because it is easier to dismiss them as monsters and turn away from what might be our cousins?”

Moving towards Bucky, Luna approached and slipped a foreleg over his withers. She stood there, her leg draped over his shoulders, and moved her head close to Bucky’s ear. “This is why I selected you as my protege,” she whispered. “For all of your darkness, for all of your madness, you have moments of incredible clarity and lucidity.”

“I want to help them. No creature deserves this sort of fate. Undead or mind control, it all comes down to slavery and I don’t like it,” Bucky growled, aware of the fact that he was a willing slave protesting slavery.

“My sister has placed her faith in Dinky and her ability to control insects. Changelings, if they were ponies, are mostly insectoid now. Dinky will need her father’s help… Celestia wants to control, I want to take out the source of the problem,” Luna whispered.

“Kill Chrysalis?” Bucky grunted in a fearful voice. “I don’t know about this… if she is a pony… or was a pony… I won’t bring physical harm to another pony.”

“Maybe not kill her, just break her power somehow,” Luna said soothingly, still speaking into Bucky’s quivering ear. “Killing her would be a terrible option. I hope we can find another way, but she remains a threat to us. And she holds thousands and thousands in her thrall. They deserve their freedom.”

Squeezing his eye shut, Bucky pulled his head away from Luna, grimacing in pain. “It almost sounds like you want for me to break my vow, using guilt as a lever."

“I want you to find some way of breaking her control, enchanter. Not now of course, but in time. In the meantime, I am going to have my tacticians plan for an excursion into Las Pegasus. After you are done visiting Griffonholm, I might have a task for you. I strongly suspect that you could infiltrate Las Pegasus and have a look around. You wouldn’t need to kill anypony, just do whatever is needed to subdue and pacify them. We need intelligence. I am not sure about my course of action just yet,” Luna said in a low voice.

“This is wrong. We shouldn’t cut apart and torture this changeling. It should be destroyed and put down. Put to rest. Given an end. I know studying it is important, but this feels wrong." Sentinel said in a low strained voice.

“If only we had the luxury of morality,” Luna replied regretfully.

Author's Notes:

A lot was said in this chapter. Take notes.

And exterminate the topys.