Cozy Glow didn't appear to notice Flash Sentry when she departed the headmare's office. She just trotted away while commenting to herself. "That chancellor is going to ruin everything! Does he know? I can't risk him finding out, I must find some way to stop him like I did the prince!"
Those comments were enough to get Flash Sentry interested. He remembered having heard in passing from his captain that Cozy Glow had been rather unusual from the day she first arrived at the school. Was her strange behavior a ruse to keep ponies in the dark?
Well there was no way to know for sure, but Flash immediately took it upon himself to get to the bottom of the mystery that presented itself before him. "Whatever twisted scheme you're planning, Cozy Glow, I'll stop you," He thought to himself, and then sighed. "Kids these days. Why can't they be more like my niece, Scootaloo? There's a filly who knows how to keep herself out of trouble, most of the time anyway."
But after only a little bit of tailing, Flash found that Cozy Glow seemed to have given him the slip for the time being. He was just about to consider calling it a night, when he happened to hear a muffled sound coming from the library. He couldn't be sure but the pegasus thought it sounded like somepony opening a grate.
As fast as his namesake might imply, Flash bolted to the library without a second's hesitation! The door was unlocked, Cozy Glow had to have come this way.
Making his way past the book shelves, the pegasus stallion scanned back and forth across the isles for any sign of Cozy Glow or anything else that might be unusual. When he reached the back of the library, his left eye happened to spot what appeared to be an open grate. He rushed toward it. It looked like he could fit down there if he squeezed himself in. So that's what he did, tucking his wings to either side of himself as he slowly forced his way down through the grate.
Once safely below, Flash had little time to get his bearings before a most unusual sight greeted him. A series of strange, glowing crystal catacombs greeted his vivid cornflower blue eyes which widened in shock! "What is this place?! It's like nothing I've ever seen before." He commented.
The stallion trotted forward, taking in the sights and sounds of his surroundings. Did Cozy Glow know about this place? Was she the one who had left the open grate that had allowed Flash to gain access? And if so, why would she do such a thing? Why leave a trail for somepony to follow?
Then Flash's ponderings were interrupted when up ahead, what should he see but the familiar outline of Shining Armor?! It looked like something had happened to him, he appeared to be glowing ever so faintly! "Captain!" Flash shouted at the top of his lungs and rushed towards his superior at once! "It's okay, Captain Armor. I'm here now. What happened?! How did you get out of Tartarus?!"
"Shining Armor" spoke very slowly and weakly, as though every second he existed something was sapping all of his strength. "I... could not stop this from happening. It is... too late for me."
Flash shook what he believed to his captain quite hard! "What are you talking about?! That's crazy! You're gonna be okay, Captain!" Then he narrowed his eyes and growled. "Who did this to you?!"
The alicorn spoke slowly once again. "A force unlike anything I have ever encountered. You must stop.... her... before it is too late for any of us. Alas, my time grows short." And he faded into a series of glowing specks.
Flash was horrified! It took him a moment to realize that what he had seen was not in fact his captain! "Whoever that was, I won't let you down! I'll avenge you!" He vowed, and boldly trotted forward once again!
Flash Sentry soon discovered a clearing. When he entered it his eyes were momentarily blinded by the brilliant light that emerged. Once he had regained his vision he could hardly believe what he saw!
A series of six artifacts were placed around a circle. Said circle had carvings and engravings like the kind you would see in high level spells. They held up some kind of bubble which was suspended over a huge pit glowing and swirling with magic. And the artifacts themselves were each surrounded by an energy field. When Flash reached a hoof out to touch one of them, he received a nasty shock and was thrown back!
Shaking himself off, the pegasus stallion suddenly realized what the objects were: Clover the Clever's Cloak, the Crown of Grover, the Helm of Yksler, the Amulet of Aurora, the Talisman of Mirage and Knuckerbocker's Shell! "These artifacts were in the Canterlot archives the last time I saw them! How did they end up here?!" He thought to himself.
Just then the sound of hoofsteps caught the stallion's attention. Spinning around he found himself face to face with none other than Cozy Glow herself. "Golly, Mr. Flash Sentry. What a... surprise to see you here."
"Funny, I could say the same to you, Cozy Glow," Flash growled as he locked eyes with the filly. "It's no use playing innocent with me. I know you're up to something, I heard what you told Chancellor Neighsay!"
Cozy Glow gulped and back away slowly. "P-please, Mr. Flash Sentry, this is all a big misunderstanding. Neighsay's the bad guy, not me. I'm just a filly."
"You expect me to believe that?! I doubt even Neighsay could've set all this up without anypony being any the wiser," Flash snarled as he trotted towards Cozy. "It's your fault my captain's stuck in Tartarus with no way out! You knew he'd go rushing off to there the moment the magic in Equestria started to fade! I don't know why you'd want him out of the way, but your plan ends here! You're going to undo whatever it is you've done this instant, Missy!"
However, Cozy's eyes suddenly glowed as she slumped to her knees and put her hooves to her head. "No, Master! Please, not now! I just need more time!" She let out an ear piercing scream as her eyes suddenly glowed lime green.
"Cozy Glow?" Flash commented as he stepped back in surprise.
But a deep, raspy voice spoke through the filly. "Not exactly. Cozy Glow can't hear you anymore. She is my puppet now, a puppet I regret giving free will to. She does as I say."
"That voice!" Flash realized in an instant! "Lord Tirek! So you are behind of all this!"
Through the body of Cozy Glow Tirek cackled with sadistic glee. "Guilty as charged. But I'm afraid I can't allow you to interfere. There's been enough mucking up of my plans as it is with this disobedient young one! You're not getting out of here to warn the others!"
"Just try and stop me!" Flash declared as he unfolded his wings. "There might not be much magic left in Equestria, but I've still got enough left in the tank to outrun you!"
But the moment Flash tried to flap his wings he felt himself be struck by a bolt of dark magic that paralyzed him and rendered him helpless! Tirek's voice ominously echoed. "You pathetic ponies always love to play the hero, don't you? But this time there is no hope for any of you. I'm going to get my revenge, and there's nothing any of you can do to stop me!" Cozy Glow's body then picked up Flash, tossing him effortlessly into the bubble as though he were made of paper.
However, just a moment later Cozy blinked and the green glow to her eyes faded. She panted quite heavily. "Sorry it had to be that way, Mr. Flash Sentry. But Tirek is my master and I will do as he commands. Now you'll pay the price for your interference," With a smirk she added. "Don't worry though, you may get some company in there soon. Besides, in another day or two that bubble will sink into another dimension. And with it will go all your precious Equestrian magic. All will bow before Lord Tirek!"
Flash Sentry could only watch helplessly from the bubble as Cozy Glow trotted away. "I'm sorry, Captain Armor. I failed." He thought and became rather forlorn. It truly seemed like this time, the bad guys had won.