"This is the spot, right?" Smoke asked, studying the red carpet below him.
Rarity nodded. "Roughly, but yes." She focused her attention on the ground as well. "What... exactly are we looking for?" she asked after a few moments.
Smoke suppressed a grin. "Anything unusual, really. There is always the possibility that Princess Twilight was poisoned with regular venom, through some sort of trap set up here. But it's very unlikely, she would have probably noticed she'd been stung or something of the like. And even then, any signs of the trap would probably have already been removed. Still, doesn't hurt to check," he explained.
Rarity chewed on her lower lip, wincing slightly. "We should have been more careful."
"Don't worry about it. It's not a mistake when you couldn't have known what was going on at that point. And Princess Twilight would be just as much to blame for not notifying that she'd been stung by something, if that really were to be what happened," Smoke reassured her.
Rarity grimaced. "She really doesn't take her role as princess as seriously as she should. An attempt at harming her like this was bound to happen sooner or later."
The pegasus looked up at her, still somewhat focused on the carpet. "She has decided not to keep any stable body of guards, right?"
Rarity nodded, a touch of annoyance towards the alicorn creeping onto her face as she thought about that.
Smoke gave one last look at the floor, then dismissed it and began to walk down the hallway, tracing the path Twilight and Rarity had taken backwards. "That certainly complicates things. If, say, she was poisoned through some food she ate. Having a guard taste her food for her would have prevented that."
Rarity walked up to him, and curiously asked, "Does Princess Celestia have an official food tester or something of the like?"
"She doe-" Smoke stopped. "Well, she doesn't now, not any more. Her own poison melts through pretty much anything she eats, so it neutralises whatever harmful substances may be in her food. But she did have one. Though it was never revealed who it was, and voices said it was a different pony every time. It's the risk with keeping guards, you got to make sure someone else doesn't buy their loyalty."
"That does sound like a problem, yes," Rarity agreed.
The pegasus stopped and pointed a hoof at a corridor. "You came from there, right?"
Rarity put her hoof to her chin, thinking for a moment. "Yes, that should be it. That there is the entrance to the hall, right?"
"Yep. I don't think we need to check that one, it was a room full of guards, after all," he said, heading down the corridor. "Although..." He stopped in front of the large doors.
Rarity stopped at his side. "Something the matter?"
Smoke clicked his lips. "Well, if we assume Princess Twilight was poisoned before coming to this room, and that's what we're doing, since no one would be foolish enough to attack her in a room full of guards, then that raises a problem. How much control did the culprit have over the time it took for the venom to take effect?" He looked at Rarity.
The unicorn raised a hoof to her lips, pondering. "They couldn't have known how long Twilight's speech would last. And if she'd passed out in the middle of it, in front of a room full of guards..."
"It would have caused quite the commotion, right?" Smoke finished for her.
Rarity frowned in concentration. "But if the risk was there, wouldn't it have been beneficial for them to run away after poisoning Twilight, instead of being there when it happened?"
"There is always the chance that the venom responded to a trigger, and that they were following Twilight to activate it at the right time," Smoke explained. "But in the more likely scenario in which that wasn't the case, then it would have been beneficial for them to be there. In the confusion, it would have been easy to manipulate the guards into following false leads, or to slow down the investigations. Or even just to see what their plans were."
"But wouldn't they have run the risk of getting exposed that way?" Rarity asked.
"If they were in the room," Smoke replied, "then they were most likely pretending to be a guard. Changelings are experts at manipulating others and at impersonating, and if they got into the room they probably took the place of an existing guard who's now locked somewhere. Without proper training against mind-reading spells, the guard's memories are completely open to the changeling, it would be almost completely impossible to tell them apart without spending a large amount of time being personally close to then. And that opens you up to their hypnosis."
Rarity shivered. "It really is a good thing that they are on our side now."
"Not all of them, it seems," Smoke grimly commented. He took a step forward, and opened the doors, beginning his search for clues.
Following behind him, Rarity asked, "Do you think... Do you think this might be Queen Chrysalis's doing?"
"Unlikely," the pegasus replied, giving a brief look at the steps of the platform before moving on to the centre of the room. "This doesn't seem like her style. She would never accept leaving Princess Twilight like that, either she'd capture her or confront her directly. Leaving her to sleep and then disappear? Doesn't sound right, she'd at least try to replace her. But I don't think she'd go after her first, personally."
Rarity walked up to him, her eyes scanning the floor as she attempted not to focus on how the tapestries' colour didn't quite match that of the decorations on the ceiling. She asked, "What do you think her plan would be?"
"First, approach Celestia while she's unguarded, possibly during her sleep," he replied, moving on to examine the nearest wall. "Use a disguise to trick her, maybe Princess Luna or Princess Twilight, one that makes her relax. Then, try to hypnotise her." He lifted an arras to look behind it. "At that point, assuming she falls, either take her place or manipulate her from behind. The next step would be taking care of Princess Luna and Princess Twilight, as they might be able to figure out something is wrong, it's debatable which one she should go after first but knowing her it would likely be Princess Twilight, just for the sake of revenge." He let go of the arras and started to walk towards another one. "Once she falls, capture and hypnotise the other as well. And then move on to the Crystal Empire to finish the job, taking both Princess Cadence and Prince Shining Armor. At that point she'll have gotten rid of all the major threats to her."
"What about young Flurry Heart?" Rarity asked, "Or Starlight, or those who helped her defeat Chrysalis? And wouldn't it be much harder to keep things a secret without changelings to use to replace other ponies?"
Smoke stared at her. "Look, we thought about that plan years ago, okay? Things changed since then."
Rarity paused. "You'd thought about it?"
Smoke nodded, moving to look behind the second arras. "The Royal Guard isn't as incompetent as some ponies say it is. Far from it, actually."
"Then how did Chrysalis manage to capture all the princesses?"
Smoke let go of the tapestry. "Because they didn't expect there to already be changelings amongst them. Chrysalis knew their every move in advance, she'd acquired quite a bit of useful information from Prince Shining and with time it paid off, allowing her to replace members of the Guard without anypony noticing."
"I... Interesting..." Rarity replied, seemingly focused on something else other than their conversation. After a moment she shook her head and looked down from the spot her eyes had drifted to.
Smoke screen noticed this, and curiously asked, "Did you find anything?"
"Oh, no, nothing important, probably," the unicorn dismissively answered.
Smoke looked around himself. "Well, I'm not finding anything here, so if you've got something it's always worth a shot."
Rarity bit her lip. "It's that one spot on this arras here. It's up there, see?" she asked, pointing a hoof upwards. "It's a little more faded than the rest."
Smoke squinted, staring in the direction pointed at by Rarity's hoof, then took flight to give a closer inspection. "You're right!" he said, floating at the tapestry's side, "It is a little more faded in this area." He put a hoof under his chin. "Say, what causes fading like this?"
"Well, usually it's exposure to sunlight," Rarity answered. "But, you know..." She gestured around the room.
Smoke chewed on the inside of his cheek for a moment. "Unless..." He looked back at the faded area for a moment, then moved upwards and began to inspect the ceiling.
Rarity followed him with her gaze, perplexed. "What are you-"
"Ah!" Smoke interrupted her with his half-yell.
"Found something?" asked Rarity with sudden excitement.
"It looks like it!" Smoke replied, a side of his face pressed against the ceiling. "There's a hole here! It's pretty small, and you can't spot it looking up from down there, but it's definitely big enough to spy through. It looks like there's a room on the other side, though I can't see much."
Rarity's face lit up in realisation. "So maybe they didn't need to take a guard's place to spy on Twilight."
"Exactly," Smoke replied, coming back down. "I think I know where that room's supposed to be, it's hidden behind a wall but I've been there a couple of times. And I know for a fact that hole is not visible from the other side the way it looks like it should be, which means that even if it might have already been there it was opened recently, and possibly left open by someone who left in a hurry. If they left any traces, it's there we should look for them."
Rarity energetically nodded. "Let's not waste another minute then."
Smoke nodded in agreement, and the two quickly walked out of the hall, the pegasus leading the unicorn down a corridor and up a flight of stairs.