The group of guards (mostly changelings) who were escorting the four ponies to the cavern of Belemoor couldn't help but overhear snippets of conversation... But they were unable to interpret what they heard, mostly because it was too disjointed.
"... and the latest album by the Marvelous Mares was pretty good, but I think they phoned it in some of the later songs..."
"... really wanted to go to that party. It has a lot of reputation as one of the best shindigs in the whole marezona..."
"... and then the goalkeeper totally missed when he jumped for the ball and turned what should have been an easy victory..."
"... totally ended in a cliffhanger and I'm gonna have to wait another three weeks before the next issue comes out..."
Of course, that was on purpose. The four ponies who were being escorted were actually Twilight Sparkle, Pinkie Pie, Rainbow Dash and Scootaloo. They wanted to pass the impression of being only ordinary tourists, so they had used a weird but effective counter-espionage technique. While normal conversations had a certain rhythm to them, that could be followed to the point where eavesdroppers would be able to understand the gist of things by focusing their hearing during the crucial parts, what the ponies were doing was far from ordinary conversation.
Each of them was in fact doing a monologue about whatever came to mind, and talking past each other. With this, even skilled eavesdroppers would see that the conversation didn't follow the patterns of a group making united plans, while talking in code for example would lead to them understanding the flow of the conversation and being able to gleam valuable information despite not understanding the code. What the four were doing read only as random jabbering, and it truly was, but any important comunication could be done via eye language (except to Scootaloo, who didn't have training to follow any plans that required such secrecy) and the spies in the guards would get the impression that their charges were harmless.
And this technique was so easy to do that even Scootaloo could contribute, despite her being a completely normal filly.
They were already getting pretty close to the cave, and the four couldn't help but remember about their part in this plan:
1 Day Earlier
"Somepony needs to check on the cave of Belemoor and the protections around the Amulet of Threshold." Twilight said "We need to figure out the most we can about the state of the defences, what are the methods the changelings are trying to use to get around those protections, if they already started trying to do so or are waiting until they get an even stronger grip on the situation, and how long we can expect the defences to hold." She sighed "Since I'm the best at simple magical analysis, and I made sure to read all the documents relating to the cave, I'll have to be part of the group. But who else is going to go?"
Trixie, as usual, had some cogent points "We have to think about the level of danger of each operation. You might be really good at doing analysis without being noticed, and you might not be getting close to any sites with a high possibility of containing hidden changeling bases, but considering it is most likely their target, the cave will probably be watched with great intensity, and being trapped in such a place would be a bad situation." She moved one of her hooves, thinking about it "In that case, it will probably be best if you were to go with a group capable of making fast escapes even in the worst case scenario."
"In that case..." Sunset intervened "I think you should send along Pinkie Pie, because an expert in chaotic shifting is very difficult to trap," she pointed at the earth pony "Rainbow Dash, because she's fast and strong enough to break through any ambushes," she pointed to the pegasus "and Scootaloo, because she's light enough that Dash can grab her and carry her out of danger." She pointed to the filly "There's also a need to maintain the cover as sisters, and the fact that having a foal along will reduce their wariness."
Scootaloo raised her hoof "And there's also the emergency teleportation thing."
Sunset nodded "That is also a factor, but I'd prefer if this was an absolute last resort." She closed her eyes for a second "You three should also take one of Fluttershy's feathers, and in fact everyone should have one of them, for us to be able to remain in contact with her even in the worst case scenarios."
There were no objections to this arrangement, and so it was done, and soon all of the ponies present had one of the feathers of the empathic pegasus.
"Dears..." Rarity spoke after they were done with that "I can barely believe it, but you never actually told us what this Amulet of Threshold is capable of doing. What would the Changelings want with it?"
"Oh..." Twilight rubbed her head "I think we got distracted." She sighed "To put things simply, the Amulet of Threshold allows the user to create magical thresholds with special rules on them, like strenghtening all your allies and weakening the enemies. Since the changelings are a very large and well coordinated group, having the amulet would give them some really big advantages, as you might expect."
While that group of four was heading to the Belemoor cave, another group of four was doing a long trail around the village, with the goal of seeing the envinronment of the surroundings.
Those four were also being escorted by a group of guards (again, mostly changelings, the changelings had done a pretty through infiltration job) and they were also using the same technique to prevent from arousing suspicion. However, their mission was fairly different, and that was reflected in their members.
They were Trixie Lulamoon, Applejack, Applebloom and Bunker Breaker, and the filly had been drilled fairly severely in not letting on what she knew about the operation. Her part in the plan consisted of complaining that she was tired, with Bunker Breaker 'deciding to be a gentlestallion' and offering to carry her.
It was necessary because, different from the first group, they would have to go off the beaten path to be able to complete their task. And when the group was passing near a pretty hilly area (not a part of the trail) Trixie started the operation.
"Hey! Want to see a trick?" She asked her travel companions, but acted before they could answer.
Trixie's horn glowed and she started shooting multi colored sparks to the air. That was a fairly simple fireworks spell, and Trixie would never consider it a trick worthy of note, except that her real trick was the performance she was about to give.
One of the sparks "accidentally" shot out without a lot of power and couldn't fly too far before coming back down on top of Trixie's body, where it started to smoke, because Trixie had used a more dangerous version of the spell, that was based on fire instead of just light. And then her coat caught on fire.
"AHH!" She screamed and started running wildly "I'M ON FIRE! I'M ON FIRE!"
The pegasus guard took off and flew directly at Trixie, before gathering water from the air into a sphere.
"Don't worry, I can-" The guard started saying.
"HOT, HOT, HOT!" Trixie screamed and contorted her own body, throwing her rear legs back and "accidentally" bucking the pegasus on the side of the head. Such a hit while unprepared caused the guard to lose consciousness and fall to the ground.
The unicorn apparently didn't even notice what she had done, she went back to running around (going to a direction in which there were no guards) and screaming "SOMEPONY HELP!".
The two earth pony guards took off, trying to catch Trixie to be able to smother the flames. However, she was fast, and they had been a certain distance away from her, so it took seven seconds before the first of them managed to catch up. He was just about to grab Trixie when:
"Water! Water!" She screamed, and used a spell to try to shoot water from her horn to douse the flames. She missed her own body completely due to the awkward position, and the jet of water was shot out with such volume that it managed to hit the eyes of the guard, blinding him, as well as his hooves, making him slip and fall. The other earth pony guard that had been running after Trixie was tripped by his suddenly falling partner, and fell to the ground as well.
Finally, one of the guards, an unicorn (who wasn't a changeling), and had been following behind the earth pony guards at a sufficient distance not to be tripped, managed to get his wits back together and hit Trixie with a homing ice spell, that immediately doused the flame (which had already spread to most of her back). The unicorn let herself fall on her side.
"Oh, thank you!" She praised the guard, before trying to get up and grimacing "Ah, I think there are some burns on my back." She turned to the guard and asked "They don't feel that bad, but could you look anyway?"
The guard did so, carefully inspecting the burned area while Trixie did her utmost to avoid moving her back (making lots of funny faces and gestures that kept the guards' attention on her. The unicorn pronounced his veredict:
"It's really not bad, mostly it just burned your coat and only a small patch of skin was affected. How about this?" He used a spell on the burned area.
"Ohh..." Trixie said, as the white lines of the spell moved through her injury and brought relief "That feels much better. In fact..." She slowly stoof up "I can move okay, now! What was it?." She asked.
"Just a small first aid spell, miss. Mostly it protects the place form further harm and reduces the pain." The unicorn stallion answered.
"Thank you! Thank you!" She shook his hoof and smiled.
"Right..." Another guard (this one a changeling) spoke "if there isn't anything else, and if everyone agrees, we should return to doing the trail."
"I have no objections." Said Bunker Breaker.
The filly on his back said the same thing, and Trixie also agreed.
"Wait..." Another of the guards said "Where's miss Diamond Cutter?"
Diamond Cutter was the fake name Applejack had been using (her disguise had a diamond cutie mark), and the guard had a pertinent question, because in the time everyone had been distracted by Trixie's "accident", the farm mare had completely vanished.
"Sis?" Applebloom asked "Did my sister disappear?"
Everypony looked around frantically trying to spot Applejack in the distance or something similar, before one of the guards remembered to look for traces and managed to find a few hoofmarks going straight into the hilly area nearby.
"Did she get scared and run off?" One of the guards wondered.
"Maybe she simply wandered off without realizing it." Another put forth his theory.
"Regardless," The unicorn guard put in his own two bits "We can't just stay here while she's missing. One of us needs to go find miss Diamond Cutter and bring her back."
"I'll go." Another guard (who was a changeling, and actually they were all changelings except for the unicorn) volunteered, before setting off.
"Well..." A guard said "We should get going. They will eventually catch up with us."
The group, now missing two members, returned to walking the trail, except the tourist ponies were all looking concerned.
But of course, all of them, especially Trixie, were grinning on the inside as the first phase of their plan had gone off without a hitch.
1 Day Earlier
"This area here is very suspicious." Trixie said, putting a hoof in a certain point in the map "It's a place where very few ponies walk around, but all those hills would serve as a great place for Changelings to excavate tunnels where they can hide a base."
"Ah guess if Ah can get close enough ta the place, Ah would be able to see if there's any hidden bases there." Applejack said.
"Indeed, but the problem is actually getting there." Twilight pointed out "The closest a tourist can get to that place is a trail that passes somewhat close to the border of the area. But because of the problems, there's always a group of guards protecting the tourists that to outside of town."
"This is a smaller problem than you'd expect." Trixie smirked "Trixie just needs to use her magnificence to completely steal the attentions of the guards for long enough for you to escape the group. And then you'll be able to do your recon before they track you down to bring you back."
"Are you sure?" Rarity doubted "I don't think the guards will be interested in watching a magic show enough to lose track of everypony. They are well trained. And their changeling members have really good coordination."
"Who said anything about a magic show?" Trixie said smugly "Guards have to help other ponies, so Trixie figures she'll be able to catch and keep their attention by setting herself on fire. And after that it's just preventing them from saving her for long enough."
Fluttershy raised a hoof "Are you sure, Trixie? Setting yourself on fire... seems pretty dangerous."
"You don't need to worry, Fluttershy." Trixie waved her concerns off "Trixie may not have an aura defence as powerful a Sunset's, but she has enough fine control to be able to limit the damage of the fire and suppress the pain." The unicorn shrugged "It wouldn't be the first time Trixie had to do something like this."
Sunset and Twilight nodded, though the later did so with a sad expression.
The others in the room thought about asking for details but decided they probably wouldn't like them.
And at the same time the other two groups were doing their missions, yet another group of ponies was on a mission of their own.
They were Sunset, Fluttershy, Rarity and Sweetie Belle. Different from the other groups, they didn't have a group of guards escorting them, and the reason for that was because they were only wandering throught the town, so the guards posted all over the town would be enough to protect any tourists doing this kind of thing.
The four were also using the anti eavesdropping measures to seem just like normal tourists, but in their case the most important part of what they were doing was related to the manner in which they were moving around the town.
It seemed random, with one of them pointing out something interesting every so often and the group rushing to get there, but in fact the four had poured over a map of the town until they managed to find a route to be able to go over most of the area of the town.
Sweetie Belle was mostly enjoying herself, this was still a place different from usual which she toured together with her sister, but the three mares had fairly important jobs.
Sunset Shimmer, since her perception abilities weren't good enough to help with the current mission, was simply keeping an eye on the surroundings to be ready to act immediately in case of trouble.
Rarity was using some fairly subtle spells to improve her perception of the magical energies of the place, in order to be able to discover anything interesting that could be seen in the village.
Fluttershy had the most complicated work, she was keeping her empathic senses open to try to detect anything she needed to know, but was also surreptiously catching the small animals of the village and asking if they knew about anything unusual happening there.
Searching the town was an important step in their plans.
1 Day Earlier
"We should also search the town, just to make sure we can predict any unwelcome surprises." Sunset said.
"I guess me and Fluttershy are the best suited for this." Rarity decided "I should be able to notice any special hidden spells while she ask the animals of the town."
"I-I think I can also feel the emotions in the air enough to be able to detect sneaky things." Fluttershy said uncertainly.
"If you could do it, it would be good." Twilight agreed "Also, you said you felt a lot of love radiating from Venus. Do you think you could detect her?"
"... It's possible." Fluttershy spoke after a moment of uncertainty.
"So, I guess we need to make a route throught the city to be able to check everywhere." Sunset concluded "Who has a map?"
Meanwhile, Night Time was bored, waiting inside the room.
"I know my part of the plan will come only once night falls..." She said to herself "But this is still so boring..."