That very night when Rarity was abducted, Spike, Stone, and the girls were in Twilight's room talking with astral forms of Celestia and Luna.

"And she was gone." Twilight finished telling the story.

"This is serious." Celestia said with worry.

"What could've abducted her?" Rainbow asked.

"Based off what Twilight just told us there's only one being capable of performing what just happened." Luna began.

"Who?" Fluttershy inquired.

"Nightmare Moon."

"What?!" the group gasped.

"But that's impossible." Twilight said in shock.

"Yeah. I mean weren't you Nightmare Moon?" Pinkie Pie asked.

"And we purified you." Rainbow added.

"True, but the darkness that corrupted me and turned me into Nightmare Moon had to be behind it." Luna explained.

"The darkness?" Spike asked.

"Correct. I became Nightmare Moon due to my bitterness and jealousy, and that was fueled by a dark power that turned me into the dark pony. But now somehow that darkness has survived and has taken refuge inside of Rarity."

"We got to help Rarity." Spike said.

"But how, we don't even know where to begin looking." Applejack noted.

"I can help," Luna offered, "The darkness was once a part of me. But even thought we've separated I can still track it."

"Yes! Score advantage for us." Rainbow cheered.

"I suggest you all get ready. I'll send Luna by soon enough." Celestia instructed.

"Yes, Princess." they nodded, as the two astral forms of the princesses vanished.

"You heard her. Let's hurry." Twilight instructed her friends.

They all went to get their regular clothes on, and while Spike was in his room, he thought to Bahamut, 'We're going to be going up against one of our own friends. It's gonna be even harder to fight her unlike fighting Snips, Snails, and Sunset Shimmer.'

'Regardless of the matter, you mustn't let your personal feelings come between you and the job. Especially if it involves the darkness that was once Nightmare Moon.'

"Right. We do this for Rarity." Spike nodded with a pumped fist.

"Spike, are you ready?" Came Stone's voice form outside his bedroom.

"Coming." Spike said, as he left his room to join them.

They stood outside Spike's place, as a portal opened up. Out came Luna in anthro form, "Good, everyone's here."

"Yeah. Now let's go get Rarity back." Sunset said.

Luna nodded and concentrated her magic, "I'm picking up the traces of darkness. Follow me." she took it to the air and followed the trail.

"Come on." Twilight ordered, as she flew off carrying Sunset Shimmer.

Rainbow flew while carrying Applejack, followed by Fluttershy, Spike, and Stone, while Pinkie surfed across the sky while forming an ice bridge.

They followed Luna until they arrived at the same warehouse that the darkness brought Rarity too. Luna turned to the group, "This is it. This is where she is."

Twilight used her magic to scan the building, "No sign of any traps. At least none my magic can detect."

"Still, we should move in with caution." Stone said.

"I got your caution!" Rainbow flew at the doors tackling them wide open.

The others ran inside, as Twilight spoke to the rainbow haired girl in sarcasm, "Thanks, Rainbow. Just barge in. They'll never see that coming."

They looked around seeing the whole place was dark, until Twilight shed some light with her magic. They split up and looked around.

"Rarity?" Applejack called out to.

"Rarity?" Rainbow looked around.

"Rarity, where are you?!" Pinkie shouted.

"Come on, Rarity where are you?" Spike asked in worry, as he looked around.

"Girls, help!" came Rarity's voice.

"Rarity?" they asked, as they saw in a shadow of a corner appeared to be Rarity looking injured.

"Help me." she pleaded.

"Rarity, I'm coming!" Spike ran towards her.

"Spike, wait!" Luna called, but Spike had already reached Rarity.

"Rarity, thank goodness you're..." Spike was cut off as the figure of Rarity emerged from the shadows revealing to be her new evil form.

The evil Rarity grabbed Spike's arm and threw him aside. She used her magic to levitate up to the ceiling and laughed maniacally.

The group looked up in shock, as Applejack spoke, "I don't believe it."

"The essence of Nightmare Moon." Fluttershy gasped.

"Fused into Rarity." Stone added.

"It's a Nightmare Rarity!" Pinkie cried.

The villainess Nightmare Rarity spoke, "Hmm. Not a bad identity."

"Let our friends go!" Twilight demanded.

"Sorry, but this new vessel is by far better than my previous one," she looked down at the Princess of the Night, "Hello, Luna."

"Nightmare, I don't know how you managed to survive the purification thanks to the elements of harmony..."

Nightmare Rarity interrupted her, "Oh, make no mistake I thought I was done for that time. But luckily I had some help. In form of dear old Sombra."

"Sombra?" Luna gasped having recalled the memory of him as Nightmare Moon.

"Who's Sombra?" Rainbow asked in confusion.

"It won't matter," Nightmare Rarity replied, "You won't live long enough to hear about it!" she started blasting the group with dark magic emanating from the element of Generosity.

"Look out!" Stone called, as he drew his sword and was deflecting the blasts with it.

"We have to attack together!" Twilight ordered, as they powered up and went into battle.

Applejack jumped in and attacked Nightmare Rarity with her strength, "Come on, Rarity. I know this ain't like you."

"The Rarity you knew is gone! And you never appreciated the stuff I did for you, farm girl!" she knocked Applejack aside.

"Applejack!" Sunset Shimmer called, before turning to Nightmare Rarity, and blasted her with combustion.

The corrupted Rarity dodged the blasts before firing a blast of magic at Sunset Shimmer making her jump to the side, "She's more powerful thanks to Nightmare's influence."

Rainbow and Fluttershy came in and started attacking her with their elements, "Sorry to do this to you, Rarity!" Fluttershy apologized, as she blasted her with wind gusts, followed by a round of lightning bolt strikes from Rainbow.

Nightmare Rarity shook the attacks off and fired dark diamond shards at them, leaving scratches on their bodies.

"It, hurts!" Fluttershy cried.

"Little help here!" Rainbow called, as Pinkie jumped in.

"I got ya shards right here!" Pinkie fired ice shard projectiles at Nightmare Rarity's dark diamond shard projectiles.

As they appeared at a stalemate, Luna and Twilight came around from behind and blasted Nightmare Rarity with their combined magic. The dark pony took the attack, but got back up, "Good form, Princesses. But not even your combined powers can match my power combined with an element of harmony!" she laughed.

"Then how about I match your power with mine?" Spike flew in and tackled Nightmare Rarity as they rolled across the floor. When Nightmare Rarity was on top pinning Spike to the ground, he looked up seeing a good amount of cleavage peeking out form her outfit, "You know this would be an incredibly hot moment if it weren't for the fact I'm in danger."

"Focus, boy!" Bahamut called to him.

Spike remembered to focus as he promised his dragon partner and knocked Nightmare Rarity off. He spat dragon fire at his possessed friend, who back flipped away to avoid it.

"Nice try, dragon. Not!" she blasted him with dark magic.

Spike flew up and tackled Rarity, as the two grappled, "Rarity, it's me, Spike. I know you're in there somewhere. Please. Rarity, you have to remember me, remember us. We're you're friends. Please." he pleaded.

Nightmare Rarity struggled against Spike glaring at him, until her glaring eased up. She looked at Spike with concern, and asked, "Spike?"

"Yes, Rarity. It's me." Spike encouraged her.

Just when it looked like Rarity was coming, back the possessed girl shook it off, "No!" she overpowered Spike, "You will not so easily manipulate me. I fell for so many tricks before, I will not again!"

"What's wrong with her?" Stone asked Luna.

"Nightmare's essence is sinking in slowly," Luna explained, "Eventually she will bond completely with Rarity. And when that happens their minds will be one."

"We got to stop her now!" Twilight ordered, as they all went in for the attack.

They each unleashed their attacks on her, but Nightmare Rarity was overpowering them. Twilight spoke up, "We have to use the power of our elements of Harmony to defeat her the same way we defeated Nightmare Moon."

"But we need all the elements of Harmony to do it." Applejack reminded her.

"Yes," Luna agreed, "At first you were seven elements, but now it has moved up to eight. All eight elements of harmony must be together to activate. But as long as Rarity is corrupted she cannot use her element."

"Exactly!" Nightmare Rarity confirmed, "Without that you stand no chance!"

"We always have a chance!" Twilight retorted, as they continued to fight the possessed Rarity.

"You're all starting to bore me to death." she unleashed a powerful blast of dark magic pushing everyone off their feet and onto the floor.

"That hurt." Rainbow groaned.

"We gotta get up!" Applejack ordered, as they struggled up, only for Twilight and the rest of the girls minus Stone and Spike to be captured and contained in magic bubbles.

"Let us out!" Twilight demanded, as she tried blasting out of her bubble like Luna and Sunset, while the others were trying to punch their way out.

"Escape is but an illusion. You will be my prisoners forever more. And once I'm done with all of you. All of the Elements of Harmony will be used to plunge this world and Equestria into Darkness!" she declared before she and the captured girls vanished into thin air.

"Girls!" Spike cried, as he got up and saw they were gone.

"I don't believe this." Stone said in shock.

"I-I failed to protect them." Spike said, as sadness was consuming him and he dropped his head down as tears fell to the floor.