The group of ponies approached the entrance of the Crystal Empire's palace. Twilight and Spike waved to ponies who waved at them, but none approached them. Twilight was relieved because she really didn't want to try to explain her walking party until she had to. They came to the guards at the door.
"Who goes there?" Twilight thought she saw a smile from the guard start to flash when he saw her and Spike, but he quickly returned to stoic.
"Twilight Sparkle and Spike to see my brother, Shining Armor. I've brought three ponies who may be of interest to him as well, if that's OK."
"I don't see it being an issue. After all, you did save this entire city," said the guard, now being more casual. "You all may enter. I trust you remember the way to the great hall?"
"Yes, thank you."
With that, Twilight and the others went inside. Jamie was the first to speak.
"So ye saved this entire place before? That's pretty impressive! How'd ye manage that?"
"It was a group effort, actually," Twilight said humbly.
"She went through all kinds of stuff to get the Crystal Heart, which powers the town. When she got stuck she handed it to me, and I gave it to the Princess so she could finish off King Sombra," Spike interrupted. Though he didn't brag about it often in Ponyville, he did see it as one of the coolest contributions he made to a crisis situation.
"Well good for you all! An entire town powered by a crystal, though? It must be immensely powerful," the Doctor commented.
"I don't know of a crystal that could do that, but then again I didn't know there were talking ponies that looked like they were crystals until a few minutes ago," Zoe said.
"That's because of the heart. It gives the ponies that look and they have unique ties to the crystal heart. The last time the heart was taken, Sombra was able to make the entire vanish for more than 1,000 years,"
"1,000 years? That doesn't seem possible. Where did they go?" Zoe asked.
"Sombra wiped their memories completely when they disappeared, and it took the return of the Crystal Heart to return them to normal. As to the time between, no one remembers anything, so I suppose that mystery will remain unsolved."
"It sounds to me like it was some type of suspended animation, though I can't say for sure. That does sound fascinating. Between this heart providing so much power to the town and this Sombra being able to suspend the town for more than a millennium with the heart not being present, there seem to be incredible powers at work here," the Doctor said.
"Well if something powerful is causing problems, I'm sure between all of us, we'll be able to figure it out." Twilight pushed open the door after finishing speaking. Her brother ran up and greeted her.
"Twily! I'm so glad you came by to help me out here. It's the first time you've been able to visit without the fate of a city hanging in the balance."
"Well hopefully that's the case. How have things been over here?"
"Can't complain. The cold weather has been kind of a distraction, but we've been unable to do anything about that. How are you, Spike?"
"It was kind of a long trip, but it's nice to get out of the tree every once in a while," he said.
"I'm sure the townspeople will be happy to see you again. Did you know that-" Shining paused when he realized the grey pony that came in with Twilight was now wandering the room, putting his ear to the walls and ground.
"Um, I thought you might bring your friends, but the friends you brought are a surprise. Who are these ponies, Twilight?"
"Oh, right. Shining, I'd like you to meet Jamie and Zoe, and the pony with no manners over there is the Doctor."
"The Doctor? For Ponyville? What's his name?"
"It's just the Doctor," Zoe said.
"He just calls himself... the Doctor?"
"Aye. It's what we call him," Jamie said.
"And these ponies are friends of yours from Ponyville, Twilight?"
"Well, not exactly from Ponyville, but they think they might be able to help solve the situation with the weather if you'd like their help."
"I'd certainly like to have help with getting the temperature back to normal. Whatever is doing it is beyond my power to control, but I would like to know more about you all before I let you get to w-"
"Excuse me?" the Doctor chimed in from right behind Shining Armor, causing him to jump slightly. "You wouldn't happen to have an air duct around here, would you?"
Shining was taken aback at how this strange pony seemed to just throw aside all protocol and start doing... whatever it was he was doing.
"It's... on the bottom of that wall over there. On the inside curve of the wall."
"So it is. Thank you," the Doctor pulled out his recorder and began trying to play again as he walked over to the vent.
After a moment of processing the encounter, Shining turned back to the group. "What is he doing?"
"Your guess is as good as mine right now," Twilight answered.
"Does he do this often?"
"You mean wander off and explore things? Yes. In fact, this is probably the most straightforward he's been in some time," Zoe answered this time.
"Well I'd rather he not wander the castle doing... whatever that is that he's doing!" Shining turned to see the Doctor was now lying on his stomach with the end of his recorder inside the vent as he tried to play it. He wasn't even trying to play any type of tune now. It was just select notes over and over again.
"Well really, what could he do doing that?" Jamie pointed out.
"He's right, Shining. Besides, I've seen the Doctor in action - kind of - and believe me, his weird ideas sometimes really work out," Spike added.
"Fine, but I don't know how what he's doing is going to help anything."
"Did you know there's a second air vent on the upper wall in the corner?" The Doctor yelled over.
"I- Yes! So?"
"So, I need to get up there! Bring me a ladder!"
"Why should I bring a ladder?! What are you even-"
"I'll levitate him, Shining, don't worry about it. Just go with me on this," Twilight said before turning to the Doctor. "I'll levitate you! Get to the corner!"
She and the Doctor started walking over there. Admittedly, she had no idea what he was doing or even if this Doctor was being helpful. But if what the pony said was true, then she wouldn't know until he actually started doing something.
"OK Twilight, before you send me up I need to ask you, how will you levitate me? With your horn?"
"Yes, I'll use my magic, of course,"
"And when I go up, will I be encased in some sort of energy bubble?"
"Yes, that is how it works," Twilight was a tad confused by the questions here.
"Is it possible for you to levitate me by my backside only?"
"What? Why?"
"I need my front hooves free. Now send me up by my hind legs to the height where I can play into the vent."
"Doctor, what exactly are you-"
"No questions yet, please. I need to know something. Quickly!"
"OK!" Twilight focused her magic and sent him up to the vent about 15 feet up.
The Doctor immediately got to work and took out his sonic screwdriver to pop open the bottom of the vent. He then spent the next minute playing his recorder note by note into the vent. Twilight just held her focus on keeping him up there, knowing that if she shifted her focus on trying to figure him out, she would definitely lose control of the spell and drop him.
"Hmm," the Doctor mused when he finished playing. "It's just as I feared. Twilight, you can bring me down now!"
"What? Oh, OK!"
As she lowered him, the rest of the group came over. They were all gathered by the time the Doctor was back on the ground.
"This cold is not a natural cold."
"We kind of figured that," Shining replied dismissively.
"No, no! I mean the cold air is being manufactured underground. The cold air is coming out of all the air vents in this palace, and I would assume the entire kingdom!"
"Are you saying that this entire cold weather thing is a draft being let in?" Spike asked.
"But that doesn't make sense Doctor. Wouldn't everyone notice the source was the cold air coming through their own vents? It feels like its just swirling around out here," Zoe said.
"A good point, which is why I listened to the ground below. There is a slightly higher vibration underground than there is in the walls. It's minor, but I've been well-versed at sensing these mini-tremors.
"As to how they didn't notice, there appears to be some kind of factor being implemented on all the vents to make the air feel non-existent. The vent is certainly cold, but there is a small pocket about six inches outside both of these vents where air isn't felt. It's like a force field of invisibility."
"Is that why you were using your recorder?" Twilight asked.
"Exactly. When I blew my recorder outside of everything, the notes came out normally. When I put it in the vent and played, the air experienced intense resistance, so my notes were muffled slightly. And when I played with the recorder in the field, no noise came out, I couldn't even feel the air against my hands, er, hooves."
"So whatever is underneath the city is what's causing the cold," Shining said.
"Well it won't be fer long. I say we head on down and take care of this!" Jamie said.
"Hold on! If something is down there, then I want my guards heading down there to explore it," Shining said.
"Oh there is no time for that! You're as bad as the Brigadier," the Doctor complained.
"I'm sorry Doctor, but I'm not putting anypony at risk besides my guards on this mission."
"Well I want to volunteer! The Doctor will need someone who he can trust to give him information," Jamie said.
Shining looked apprehensive, but then relented when he saw everyone - even Spike and Twilight - give him a look to let him go. "Fine, but you will stay with the group at all times. I don't see why you can't take my guards' word for it, but the group will leave in 15 minutes for the passage underneath the palace."
As Shining left, Twilight approached Jamie and the Doctor. "Are you sure this is the right decision? Shining Armor's guards could look for whatever it is you're looking for."
"I'd rather someone I can trust handle it. We've dealt with beings underground in cold climates before. If someone's keeping something underground and putting out this kind of effort, it's something big. I want to know what is down there and I trust Jamie to pick up details that I can't teach guards in 15 minutes."
"Yah, don't worry 'bout me, Twilight. I've dealt with far worse things an' survived them all," Jamie reassured her.
"OK, well you'd better get down there. Shining will have his team outfitted with armor and radios soon enough."
"All right, you guys know the drill. Get down there. Figure out what the problem is and report back to me," Shining said before turning to Jamie. "If there's any trouble, use your wings and get out of there. I really don't want to risk having you down there."
"I'll be fine. Worry about yer own men."
Shining shrugged off the word 'men' as some kind of slang and sent the group into the chamber. He then spoke to the Doctor. "That chamber leads to our underground bunker, where the leadership can command in the event of an invasion of the palace. It's the only underground entrance I know of in the Crystal Empire besides the sewer entrances.
"From the end of the bunker, there is a passageway that leads into the network of sewers. I just sent 14 top pony guards in there, so we'll know fairly quickly if anything is down there."
Prof. Scope knocked on the door of Commodore Charcoal with much haste. His sensors had just gone off and he had to relay the message quickly.
"What is it Scope? Come in and make it fast. I'm trying to organize the next stages of the plan here."
Scope looked very worried. "Well, it would seem that the sensors detected a massive influx of body warmth entering the underground area. It would appear that it's about 15 all coming from the royal chamber entrance."
Charcoal actually smirked at this. "Is that all? Professor, you really don't understand how much planning has gone into this. Our allies have already been moved primarily around that entrance because it was assumed that the royalty would try to do something about the cold sooner or later.
"I honestly think it's hilarious that they believe that only the royal guard and leadership know about the bunker."
"Well it is hidden, sir. Well camouflaged by the stone surrounding it."
"I guess it's a good thing this group has the technical know-how necessary to scan for such camouflage. Now leave me. I'm going to keep to my work and I recommend you do the same. Let me know how long it takes for the ponies to be taken out. I assure you it won't be long."
"Yes, sir."
The expedition crew pushed through the secret exit into the sewer system and were now looking at the maps given to them.
"There are three major routes here, and they diverge even further after that. I say we split up three ways," Commander Blowback said. "Captain Flame, take your unit through the left tunnel and look for anything unusual. Sergeant Breaker, take yours through the right tunnel. My unit and the civilian, with me through the center."
"Are ye sure we should be splittin' up like this?" Jamie asked.
"We have no reason to believe that there is anything hostile down here. So move! I don't know why Shining allowed you down here," the commander said.
"Fine," Jamie grumbled as they headed down.
The three units all wandered for a good ten minutes. Not a sound could be heard from the other routes and the commander's group was very quiet. The only noises being heard were the occasional uses of magic, the clopping of hooves on the stone ground and the uncomfortable echo of the chamber. The temperature was unbelievably cold and it made Jamie glad they had spelunking equipment handy to allow extra warmth.
Throughout this time, the area was becoming increasingly eerie. The silence was becoming more pronounced, like the energy of the area was converging on something that could attack at any moment. Jamie was glad he kept a dirk in his clothing that he could pull out just in case.
"We've been down here a few minutes now, sir, and nothing out of the ordinary so far. We'll keep going deeper, though," the commander said to his radio.
"Understood commander. Proceed forward," Shining responded. From the guards' facility in the back of the castle, Shining, Twilight, Spike and Zoe were listening for responses.
"Shouldn't we be concerned that that's the only thing we've heard? You said they planned to split into three groups," Zoe asked.
"I'm sure if the commander's group heard anything they'd have told us, but you are right about it being a bit long. I'll radio them. Sergeant, any word?"
"Nothing yet, sir. Just been quiet the whole time. We're checking the start of the diverging paths and then returning to the center after leaving markings, so you'll have a good idea wher- what is that?"
"What is what? I'm hearing screaming coming from a ways away. It's too close to be the commander."
"Then it has to be the captain. I've gotta go." He then changed frequencies. "Captain, this is Shining Armor, have you found-"
"Oh Celestia! WHAT IS IT?! IT'S KILLED THREE PONIES!"
"WHAT?! Captain what is going on?"
"No! No DON"T COME NEAR ME! AHHHH!" The line then went out.
"Captain! Captain respond! Oh-no. Sergeant. Get out now. There's something down there with you."
"But sir, what about-"
"Leave NOW!"
"Leaving now, sir. Let's go!"
Shining changed to the commander's frequency.
Meanwhile, the commander was hearing the screaming himself. "It looks like we've found the problem. Grab your tools! We're heading down there."
"YES SIR!" The group began running back toward the main hub.
"Commander, can you hear me? There's been something found."
"Yes, sir! I'm moving my unit toward them now."
"No, you head back now."
"But sir -"
"There is nothing you can do. I'm not losing anyone else! Go back now!"
The commander had to take a moment when he heard that they'd lost a group, but he quickly responded, "Yes, sir! I'll keep my group safe."
"See that you do."
The commander's group and the sergeant's group convened at the same time in the center. Unfortunately, the attackers were right behind them.
"Sir, it was the captain, he..."
"I know, Sergeant, but we can't do anything about that now. Let's just get back in and..." he heard the roar coming. "What was that. WHAT IS THAT?!"
The creatures came into view. The two gigantic creatures were hairy and incredibly large at the bottom. Each one was about six feet tall and despite clearly being slow, it was clear from their power that these were the beings that took the captain's group by surprise.
Jamie, however, was not in awe - only in surprise that these creatures were even here. He quickly grabbed the commander's radio while he was in stunned fear.
"Doctor! Zoe! Are ye there?"
Shining Armor already had the radio on the commander's frequency and handed it to the Doctor. "Yes, Jamie. What is it?"
It's the Yeti again."
"What?! The Yeti? On this world?"
"Aye, it looks like someone's brought them here..."
"Hey! Give me that!" the commander said, getting back some of his composure. "You know these creatures?"
He didn't get an answer as the creatures came into full view and began coming toward them. The stunned-with-fear crews were reaching for their weaponry and trying to focus their magic to stop the Yeti, but it became clear they might not get the time, as the two began charging them.
***End Credits***