Author's Note
Another sequel?! Yup! Another one!
Hope you enjoy! 
Comforting The Sun
Celestia rose the sun at the balcony. After the sun was raised, she went back inside her bedroom and brushed her mane and put her accessories on. She then headed to the kitchen.
When she arrived at the kitchen, she spotted Luna. She wore a smile and wasn't grumpy as usual. Celestia was shocked. She had never seen her sister up this early.
"Sister? What are you doing up so early?" Celestia asked in a shocked voice.
"Well, I decided to stay up and have breakfast with you to celebrate my return from the moon," Luna explained, still having a happy expression.
The Sun Princess then suddenly froze. Those last three words that her sister had said reminded her of the horrible memories that were still in her mind. They had been haunting her since she first returned. Just then, she was snapped out of her thoughts.
"Sister?"
Celestia shook her head.
"Are you alright?"
It was Luna.
"Y-Yes, fine," she lied, not wanting to tell her sister what was wrong. The Moon Princess then raised an eyebrow of suspicion at her.
"Are you sure?" The Moon Princess asked, having a look of concern in her eyes.
"Yes, I'm sure," The Sun Princess repeated.
Luna could tell that something was up with her sister. She wondered why she wouldn't tell her what was wrong. She wanted to say something else at first, but decided not to. Right now, she wanted to enjoy eating breakfast with her.
"Lets just eat breakfast," Luna said, already starting to eat.
"Alright," replied Celestia, also starting to eat.
...
After the two sisters finished eating breakfast, Luna had an idea instead of going to sleep. It was a good one. It held a lot of good memories. She turned to face her older sister.
"Hey, sister?" Luna said, trying to get her attention.
"Yes, Luna?" Celestia said, now facing her.
"I have an idea."
The Sun Princess looked shocked once again.
"Another idea? I thought you were going to go get ready to go to sleep!" she said in a shocked voice.
The Moon Princess giggled.
"Yes, I know I should be doing that, but I want to show you something real quick," she replied.
"Oh, alright," The Sun Princess said, wondering what she wanted to show her.
"Follow me."
...
The two sisters were now outside in the Canterlot Gardens. Celestia wondered why Luna brought her here, but she knew she was about to find out. Luna leaded her and herself further and after a few seconds, they reached their destination. The Sun Princess gasped when she saw something beautiful.
"It's our... old fountain..." she said in a quiet, shocked voice.
"Correct," The Moon Princess said, smiling.
The sight of the old fountain made happy memories enter The Sun Princess's mind, but more bad ones were still there. Just then, she heard a voice.
Celestia...
She looked around with a frightened expression. It sounded like her sister's old evil form, Nightmare Moon. She wondered if she was hiding somewhere. Was she? She didn't know. Just then, she was snapped out of her thoughts by Luna.
"Celestia? Are you okay?" Luna asked, becoming more concerned.
"Yes, Luna. I'm fine," Celestia replied.
"Celestia, you know you can tell me what's wrong. You don't have to hide your feelings from me," The Moon Princess told her.
The Sun Princess started to become irritated.
"Luna, seriously. I'm fine," she said in an irritated voice.
"Celestia! Please just tell me-"
"I'M FINE!"
Luna stepped back. She was shocked by her sister's outburst. Celestia was also shocked by her own outburst. This caused her to run away.
The Moon Princess was now alone.
...
Celesia had just finished signing more papers. Just then, Luna entered to tell her that she can go to sleep now.
"Sister, you can head up to your room and go to sleep now. I have everything under control," she told her.
"Alright," Celestia replied, exiting the throne room.
Luna decided to stay in the throne room for a few minutes. She made her way towards the throne and sat on it. She then thought about her sister's behavior.
What's wrong with Celestia? I wish she could just tell me..." she thought.
...
Celestia woke up somewhere that wasn't in her bedroom. It was dark. She was confused. Where was she? She didn't know. Suddenly, she heard evil laughter.
"Who's there?" Celestia said, magic sparking from her horn.
Hello, Celestia... a voice said.
"Show yourself, you coward!" The Sun Princess demended.
She heard something then approach her. After a few steps, it was revealed who the voice was. It was Nightmare Moon, the evil form of her sister.
"N-Nightmare Moon?!" Celestia said, looking at her in horror.
Yes, Celestia. It's me... Nightmare Moon said, giving an evil grin.
"W-What do you want?" The Sun Princess said in fear.
Oh, you know... TO HAUNT YOU IN YOUR DREAMS! Nightmare Moon told her, laughing.
"NO! PLEASE NO!" Celestia begged, tears welling up in her eyes.
You know, Celestia, you're weak. You're a baby.
"STOP! PLEASE STOP!"
You don't even deserve to rule Equestria. I should rule it since I'm strong and not like you.
"STOP! STOP IT, PLEASE!"
Honestly, just step down already!
"I SAID... STOP!"
When The Sun Princess said those words, Nightmare Moon was gone.
...
"Sister?! Sister?! Wake up!"
Celestia jumped awake to the voice of Luna. Her pillow was stained with tears and some were still rolling down her cheeks.
"Sister..." Luna whispered to her.
Celestia broke down sobbing. Luna then got on her bed and embraced her.
"L-Luna... I-I..." Celestia tried to speak but she couldn't since of the state she was in.
"Shh..." The Moon Princess cooed softly. "Just let it out... relax... I'm here..."
The two of them remained like that for some time. After a while, Celestia was calm. She lifted up her head. Her cheeks were bloodshot and her cheeks were stained with dried tears with some still running down them. Luna used a hoof to wipe away the remaining tears.
"Feeling better now, sister?" Luna asked.
"Yes, sister. A lot better," Celestia replied, giving a smile.
"Good. Now, why don't you tell me what's wrong?"
The Sun Princess took a deep breath and then she began speaking.
"Well... I feel guilty about the Nightmare Moon incident..." she said, looking down at the floor.
The Moon Princess's eyes widened.
"Sister... you're still on about that?" she said in a shocked voice.
"Yes... and I also had a nightmare about Nightmare Moon being there saying I'm weak, I'm a baby, and that I should step down from the throne..." The Sun Princess told her.
"Celestia... I had no idea..." Luna said.
"It's fine..." Celestia said, turning away.
"Celestia, please don't blame my transformation into Nightmare Moon all on yourself..." The Moon Princess said to her.
The Sun Princess sighed.
"Alright, Luna..." she said.
"Tell you what, I'll check on your dreams for now on since I never do. Sound good?" Luna asked.
"Yes. That sounds great," Celestia replied.
"Good. Now, do you want to have some cake together?" The Moon Princess asked.
"Yes, please. I could go for a slice of cake right now," The Sun Princess replied.
"Alright, then lets head to the kitchen," Luna said.
"Alright," Celestia said.
The two sisters were now on their way to the kitchen to have some cake.
