Princess Cadence and Shining Armor managed to track down the source of the rumble using their combined magic. Both of their horns started to glow dimly while they ran throughout the castle. It took a few minutes for the married couple to finally trace the origin of the rumble to the Royal Library. The two peeked inside before entering. They saw the circular main room in ruins.
Finally entering, Cadence and Shining Armor investigated the half-destroyed room. At first, nothing could be seen, but then they heard something. The sound of a glowing horn could be heard nearby, except this sounded a little different. Upon investigating the room more, the married couple soon found that it wasn't simply the sound of a glowing horn, it sounded like a hissing horn as well.
"What could be causing that sound?" Shining Armor whispered to Cadence.
"Can't you feel that magic?" she responded. "Our magic must have been sensing it, almost like this pony's magic was a beacon."
They walked a few more meters forward before looking down an aisle to their left. It was in said aisle that they found the cause of the hissing horn. They could see a green cocoon glued to a wall, and inside this cocoon was a glowing red light. Upon a closer glance, the two ponies could see that the red light was indeed emanating from a unicorn horn that was touching the shell of the cocoon. Cadence wanted to move forward, but Shining Armor stopped her.
"We don't know what's going to happen," he explained. "Let's just wait for a few seconds."
Their wait wasn't wasted, for the red light became far brighter than it was originally. Pretty soon, the cocoon started to melt. Cadence and Shining began to shield their eyes from the bright light. Once they heard a thump on the ground near them, the couple removed their hooves from their eyes to look at the wall again. Cadence gasped and ran towards the end of the aisle after she saw who was laying on the ground. Shining looked upon the scene of his wife running over to a seemingly unconscious white unicorn, but when he walked closer, he saw that it wasn't just a unicorn, it was an alicorn.
"Soren?!" Cadence called as she sat next to him. "Are you alright?" She reached over to Soren in order to shake him awake but pulled her hoof away in pain after she touched his burning hot coat. "Ow!"
"Cadence, are you alright?!" Shining asked, trotting up to her.
"Yes, I'm fine, but why is Soren's coat so hot? Maybe he was overloading a heating spell to melt that cocoon?"
"That would make sense...wait." Cadence looked up at him. Shining was staring at the center of the main room. "Do you hear that?" Cadence became silent so she could pay attention to any small noises. Sure enough, she heard a buzzing sound increasing in volume with every second.
"It can't be," she whispered.
"Changelings," Shining muttered.
The buzzing grew louder, and soon it was replaced by hooves dropping onto the ground. An unintelligible combination of clicks and buzzes were being exchanged between two changelings. Shining Armor and Cadence readied themselves as the noises approached their location. As the two changelings turned the corner into the aisle the three ponies were down, Shining Armor felt a hoof touch his shoulder. Both he and Cadence turned to see a grinning Soren standing next to them. Soren then put the hoof to his mouth to signal both of them to be quiet.
"I got this," he whispered. The changelings looked down the aisle and, upon seeing the grinning alicorn, were about to fly out of the room. However, they weren't fast enough for what came next. Soren gathered all of the heat he used to escape the cocoon. His coat shined with a faint green as he prepared a spell. Before the changelings could fly away, a giant, green heat wave rushed down the aisle towards them. The two enemies were blasted through the opposing aisle and were slammed against a wall (the same one Chrysalis was slammed against), causing them to be knocked unconscious. After the spell was over, Soren collapsed.
"Are you ok, Soren?" Cadence asked as she used a hoof to help him up.
"Yeah...that was just a lot of magic coursing through me. Took some of my energy away is all." Soren noticed Shining Armor standing in front of him. Soren reached out a hoof to the Captain of the Royal Guard. "And you must be Shining Armor. Twilight's told me quite a bit about you."
"It's nice to finally meet the 'amazing friend' my sis has been telling me about," Shining said as he shook Soren's hoof, "although I wish it would be under better circumstances. What happened up here anyway?"
"No time to explain. Chrysalis is back, that's all you need to know. To the ballroom!" Before Shining Armor or Cadence could say anything, Soren began sloppily running out of the Royal Library.
"Well he sure is an adventurous colt, I'll give him that," Shining commented.
"He's saved ponies more than anyone can count," Cadence replied as she started trotting after Soren. "He could be lazy for all I care." The princess then ran out of the library. Shining Armor, becoming more serious about the situation, sprinted after the two alicorns. He soon caught up to Cadence and Soren, and the three of them continued to run through the castle with Soren leading the way.
"So what's the plan?" Shining asked Soren.
"I need to find two ponies before confronting Chrysalis again," he replied. They took a right towards the foyer.
"Again?" Cadence asked. "Is that how all of that damaged appeared in the library? Because you fought Chrysalis alone?" Soren said nothing more until they entered the main foyer of the castle. Soren was surprised to see that no more ponies were being welcomed inside. Not only that...
"Where's Princess Luna or Princess Celestia?" Soren wondered aloud. He groaned then gave a quick outward breath of irritation. "That's ok," he assured himself. "The plan can work without them anyway. I'm actually very glad I ran into you two before going to the ballroom. I need your help."
"We'll do anything to get rid of Chrysalis and the changelings," Shining stated.
"But that's the funny thing: There aren't many changelings in the castle right now. Think about it." Seeing the confusion etched on his friends' faces, Soren continued. "The ballroom had almost ten ponies last I checked. Without including them, don't you find it odd how we were never attacked on our way here. If Chrysalis wanted a hostile takeover, she would have brought an army with her. She would have brought an army, except~..."
"Except she's looking for something specific," Cadence finished. "But what?"
"Isn't it obvious? She wants something powerful. Possibly to help her accomplish a hostile takeover in the future, or maybe she just wants to make her changelings stronger."
"But Celestia is too powerful for Chrysalis to bring to the Badlands, even by force," Shining added.
"Who said it was the princesses Chrysalis was after?"
"Twilight!" Shining gasped. Soren still shook his head.
"Thankfully, no. Who did she cage in the library instead of destroying? Who recently became a well-known, powerful alicorn in Equestria? Who has the Elementals on his side?"
"You," they said simultaneously.
"Not to gloat, but yes, she is after only me. Why she decided to go after my friends is beyond me, but I can guarantee that she will never ever try anything like this again after I'm done with her. Come on!" Soren ran out of the foyer. Cadence and Shining Armor soon caught up with him.
"I know you have a plan. Mind telling us what it is?" Shining asked. Soren simply smiled and continued to look forward.
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Chrysalis was getting impatient. Her changelings should have been back by now. She would have sent more changelings into the castle, but she knew it would ruin her ruse. She had to keep Celestia and her subjects believing they were enormously outnumbered. Since she still had to wait, Chrysalis decided to speak to Celestia.
"So has your sister found my prisoners yet?" she asked the sun goddess. Celestia's eyes widened slightly. How did she know about her telepathic message to her sister?
"No," Celestia replied cooly, "no she hasn't. Even if we do find the prisoners, what can we do? You can still harm a few ponies, even with an alicorn protecting them."
"Very true. I'm glad you think ahead before acting, although that may have been your weakness on more than one occasion." Celestia remained silent.
"Princess, we have to do something," Twilight Sparkle whispered as she stepped closer to the princess.
"Patience, my student. Help will come, even though Chrysalis wants it to anyway."
"What do you mean by that?"
"It means that I need that alicorn over here in order to complete my plan!" Chrysalis shouted. "Now stay quiet while I wait for my three children to return. Also, if any of you interfere with Soren's plans..." She paused. "Actually, I don't think you would like to hear what I have in store." As Celestia spread her wings protectively over the group of ponies, Chrysalis began laughing.