Underneath Canterlot deep caves, Lord Tirek and Queen Chrysalis were looking for perfect place to place Twilight's group. They decided to lock them up in another chamber of the cave to prevent them from interacting with Starlight or Pillars of Equestria.

Tirek places this goo with all of them and places it on the ground.

"Here is the good spot to leave them" - he said

"What makes you think so?" - Chrysalis asked a bit unsure

Tirek took deep breath and started explaining

"Because they are away from others we caught before! We just need to separate these ponies and Discord from themselves and put them in cells separately." - then he pointed at this group: some of them began to be aware of what's happening.

"Now this is pretty clear. And what will we do with Cozy Glow? She failed after all..." - Chrysalis glanced at mentioned filly

"You know it wasn't my fault!" - she said angrily with high-pitched tone, looking like throwing a tantrum - "It was a trap, I couldn't predict that!"

"Oh please" - she huffed - "You had Bewitching Bell, I'm sure you could've easily defeated them!"

"But...why didn't you all come with me? Why didn't you support me and just flew to fight headmare Starlight?!" - Cozy asked furiously

"Wha...I just want...you know...she-starlight...I'm no longer a queen because of...um...her" - Chrysalis stuttered, but the words were failing her. After a while she mumbled an apology, which sounded like "s*muhm*rhy"

"I take that as a 'sorry'" - Cozy replied with small smirk, making Chrysalis give her short glare.

Tirek shot shots magic blasts to make cells in the walls, while Chrysalis used her magic to separate ponies and Discord trapped in goo.

Then Tirek put each one in different cell and chained Discord in his own. Finally, Chrysalis created more goo and used them as a bars to lock them up in their cells.

"Ah yes, most powerful ponies and that Discord are at our mercy. No one can stop us now!" - Tirek exclaimed, stretching his arms

"Indeed. Equestria is ours now!" - Chrysalis confirmed

"Not really! You forgot about someone" - Cozy amended

"Huh? About whom?" - Chrysalis curiously asked, glancing at pegasus filly and quickly moving her vision on Tirek

"Don't you remember? Princess Cadence? Or Shining Armor? Did you know they have alicorn foal named Flurry Heart?" - Cozy said

Chrysalis gasped, quickly recalling the time when she pretended to be Cadence at her wedding.

"Oh. You're totally right! We're heading north, Tirek! There are still some powerful ponies opposing us!"

"What about me? What do I have to do?" - Cozy frowned

"You?! You can't even defeat weak ponies with powerful artifact!" - Chrysalis glared at her

"But I can look after them! I can't fail that easy task, can I? - Cozy frowned

"Fine. You'll guard this place. Tirek, it's time to go!"

With that being said, they all went to cave's only exit to face Princess Cadence. Tirek and Chrysalis then headed to Crystal Empire and Cozy Glow farewelled them with left forehoof waving and her innocent-looking, adorable smile.

"Okay, I don't have much time" - she thought - "but I can free them, at least some of them"

Then, she flew to first chamber, where Starlight Glimmer and Pillars of Equestria were locked up.

She tries to think, who to free to help her free the others.

"Let's see" - she whispered - "Hmm. The best option is Starlight - she is wrapped in this disgusting goo, but it's not that thick to remove it from her."

Cozy Glow flew up to the cage mounted on ceiling.

There she was: wrapped in greenish goo, gagged with some cloth and had even more goo on her horn to prevent her from casting spells to free herself.

Starlight was just staring at Cozy Glow with true fear in her eyes. Cozy just smiled at her while approaching the mare.

"Don't worry! I'm here to free you. Just trust me." - she tried to convince Starlight to keep calm

Then, she opened the cage, put her hooves on Starlight's horn and started removing the goo from her horn.

It was off the horn after three minutes. Cozy then asked Starlight to cast a spell, but not to attack her, yet this wasn't possible. The filly was wondering what could go wrong. Then she remembered that shattered pieces of Chrysalis' throne spread across the cave were blocking her magic. She still could use it if one of throne piece wasn't on her cage.

"Oh, there's still something preventing you from casting a spell" - she realised what went wrong with a bit of embarassment.

Cozy Glow landed to pick some rock up. After that, she flew back to Starlight and started furiously slamming the rock on the throne piece. It soon cracked and fell down. Starlight was now able to use her magic.

"Okay, do you need my help getting you out of it?" - Cozy gently proposed, but Starlight shook her head and freed herself with magic from this goo and removed a gag.

Now, free Starlight Glimmer, stared confused at Cozy Glow, the same pony who trapped her in magical orb in catacombs underneath the School of Friendship.

"Here you go" - Cozy said timidly with small smile adoring her muzzle.

"Thank you, Cozy, but why did you free me?" - Starlight asked curiously

Cozy replied:

"Well - I feel bad for trying to steal magic from Equestria. Now I will fight by the side of Princesses if it's needed to prove I want to change. And sorry for imprisoning you in that magic orb in catacombs"

Starlight was standing still, processing what she has just said. After a while, Cozy Glow felt foreleg going across her back. Before she could react, Starlight was holding her.

"Cozy, this is wonderful that you want to turn over a new leaf. And I forgive you pushing me to this magic orb" - she whispered to her ear.

"I'm glad you forgive me, but we must hurry up and free others before Tirek and Chrysalis are back!" - she exclaimed and wiggled to get out of Starlight's embrace.

"No worries, I got this" - Starlight said and her horn started glowing

"What are y..." - Cozy wanted to ask, but before she could finish her question, a powerful wave of light-blue magic spread across the chamber, freeing the Pillars of Equestria. The spell used up all her stamina and made Starlight dizzy.
The Pillars approached the two ponies.

"Well, well, well..." - Starswirl the Bearded said calmly with gentle smile - "looks like you want to be good once again, little one"

"I do! I promise I won't let you down and prove I can be rede..." - Cozy again couldn't finish, because a hoof covered her mouth and all she could do after that was a little "mphf..." sound

"We get it" - spoke the voice of this mouth-covering hoof's owner - Somnambula - "I am the element of Hope, and I do have a hope that you will be on our side no matter what"

Somnambula removed her hoof from Cozy's mouth and put it on her mane, flattening this filly's curls. Then Cozy asked.

"So, you all forgive me for draining magic and causing harm to you too?" Six Pillars nodded and Cozy smile widened.

"But we have to help the Princesses, Twilight and her friends. They are also locked up here" - she added

"Sure thing. Lead the way." - Flash Magnus said with eager.

After a while, this group got to another chamber in the cave and saw Twilight and her allies, all trapped in Chrysalis' goo.

"Cozy! You did it!" - Twilight exclaimed with wide smile - "you didn't let us down"

Cozy Glow, happy with seeing Twilight in good mood again, told Starlight to free them. She didn't have to ask her twice - another powerful wave of magic was released and the goo disappeared. Then, Twilight and her crew, Princesses and Discord approached them. They all stopped, except Princess Celestia, who was walking further and stood in front of Cozy Glow.

"Now I see you were telling the truth - you want to change, and I, with Princess Luna, Twilight and her friends will be with you if you need our help or guidance. I'm sure Pillars are also willing to show you the right path"

"You will? Even after all I've done? I'm evil and you still want to help me? I just don't think I deserve another chance" - she asked in voice full of grief and regret. Filly's eyes were filling with tears once again, so she looked away from her.

Princess Celestia reached both her hooves to Cozy, gently put each one them on Cozy's face and slowly moved her head. Cozy resisted, but quickly loosened and let the Princess move her head. Soon, she faced Celestia's kind and soothing gaze.

"No Cozy, listen - you were evil, but that's in the past, now you want to change and be good, right? If you were still evil, you wouldn't give Twilight that bell or betray Tirek and Chrysalis and decide to free us all, would you? Or would you feel remorseful for your past actions?"

"I-I wuhdn'th. Muaybeh yuh're rwight"* - Cozy mumbled somewhat audible, because squishing her cheeks made her words distorted.

Then Celestia let Cozy go and ordered everypony and Discord to leave the cave and prepare for the attack. Cozy led them all to the exit and went with them.

Lord Tirek and Chrysalis came back with bound Princess Cadence, Shining Armor and their daughter - Flurry Heart.

"Cozy, we're back!" - Chrysalis shouted but there was no reply

Chrysalis then entered first chamber and gasped in disbelief - their captives: Starlight Glimmer and Pillars of Equestria were gone! She quickly flew to another chamber and saw the same - no ponies!

"Where is everyone?!" - Chrysalis screamed in anger and panic.

"AND where's Cozy Glow?" - Tirek asked and quickly realised another thing - Cozy tricked them to go to Crystal Empire to be on her own in caves to free them.

"She betrayed us!!! Now, Princesses, Twilight with her squad, Pillars and Discord are on the loose" - Tirek was peeved - "Oh - she will regret it..."

"Let's leave this trio from the North here and go find them!" - he added

"I'll ignore my plan to take my revenge on Starlight for all eternity - Cozy is now my target!" - Chrysalis said with true anger in her voice.

"Let's stop wasting time and go! Maybe it's not too late to stop them!" - Tirek ordered

Both villains left the cave to find them.

Author's Note

*"I-I wouldn't. Maybe you're right"