Princess Celestia stood at the centre of the throne room of the Royal Palace in Canterlot, waiting. It was midday, the sun high in the sky overhead, shining through the stained glass windows that lined the walls and throwing colourful shapes on the tiled floor. The door at the end of he hall swung open, and her sister walked into the room, blinking in the bright light.

"You asked to see me?" asked the smaller blue pony.

"Yes," replied Celestia, "this is a matter of urgency."

Luna's eyes widened slightly as she heard the last word.

"What's the matter? What's going on?"

Her older sister sighed.

"Luna, it is paramount that you assume your duties soon. I cannot keep raising the moon for you!"

" But...you know I'm not ready! Please...I can't do this...not yet..."

" You can Luna, and you will!" Celestia paused for a moment, then her voice softened. " I'm sorry. If I could give you time, then I would. But with you back here, Equestria needs both of us to do what we are meant to. If I have to control the sun and the moon, the balance of this land will change!"

Luna said nothing, choosing to let the silence do the talking.

"I know how hard it is for you to accept your place, but you are a different pony to Nightmare Moon." Celestia continued.

Her sister flinched slightly at the name of her alter-ego, but still did not speak.

"Please, Luna. Every day the power I have over the Moon grows weaker. You are the true Princess of the Night!"

For a moment, Luna looked like she was going to argue. But then she looked down, and said quietly

"I'll try to restore the balance. Equestria needs me to."

Seemingly satisfied with her answer, Princess Celestia looked fondly at her younger sister.

"I know you can do it if you truly want to."

Princess Luna stared out of the window at the peaceful land below, the land she had once tried to shroud in darkness. If she had her magic back, she could do so again. Her jealousy could confront her again, turning her back into that evil pony, the one whose reputation she had yet to erase. But at the same time, Equestria could not survive without the night. It was her night, not her sister's, and she needed to use it herself. Celestia knew that. But did she want the responsibility of bringing the moon every night?

"I'm not sure if I want to at all..."

***

Evening came, and Princess Celestia lowered the sun and pulled up the moon. For the hundredth time that day, she sighed. Bringing the night was getting harder. It would not be long before she couldn't do it at all. She stood at her balcony and stared at the stars, wondering what would happen if her sister never took her place. What would happen when night refused to come? The day would last forever, with no respite from the sun. Celestia was painfully aware of Equestria's need for both night and day, no matter if anypony wished otherwise. If the sun never went own, what would her subjects think of her? Perhaps they would believe she had become evil, refusing to lower the sun for Luna's night.

She shook herself. She would never allow that to happen. It was her duty to maintain balance for all of Equestria, and she would, whatever happened.

"Come on, little sister," she whispered at the sky, "find your true calling. All of ponykind needs you to accept who you really are..."

Then she had an idea. Using her unicorn magic, she flew a quill, an inkpot and a blank scroll out to where she was standing. Quickly dipping her writing tool in the ink, she penned a letter:

My dearest student Twilight,

I have an urgent request for you. I require your researching skills to help me resolve a problem that concerns all of Equestria.

I want you to find as much information as you can on how young ponies earn their cutie marks. This may sound like quite a trivial subject, but it is extremely important. My sister is having trouble regaining the use of her powers to raise and lower the Moon.

Whilst I realise that Luna already has her cutie mark, I believe any books you have on the matter will help. Getting your cutie mark is about discovering who you really are, and I think that Luna needs to do this if she is to become bringer of night once more.

Your mentor, Princess Celestia.

Celestia sent the note. She knew she would not get a reply until morning, but perhaps knowing the letter was on its way would set her mind at ease.

Once again, she sighed. She hoped tomorrow Luna might realise how important her task was. But in the meantime, it would be her struggle to bring nightfall.

She just hoped she could do it.

***

Twilight Sparkle was awoken by early morning birds twittering outside her window. She rolled sleepily out of bed and over to her mirror, where she brushed her unruly mane into submission. Then, quietly, she tiptoed downstairs, just in case Spike wasn't already awake. Glancing at the basket where he was still snoring, she spied a rolled-up scroll lying beside him. She immediately recognised the royal seal, and decided to risk picking it up with her magic. Gently, she lifted it up into the air. Spike rolled over, and Twilight winced. But luckily, he only mumbled a few words before beginning to snore again.

Twilight read the letter, and creeped down to the library. Searching through her hundreds of books, she eventually came across the one she wanted.

"A cutie mark is a symbol displayed on a pony's flank that depicts their true talent. Ponies are born without a cutie mark, but earn it when they discover who they truly are."

Twilight sighed. She knew all of this already!

She flicked through the rest of the book, trying to find something useful.

A particular passage caught her eye.

"While most ponies need not worry about forgetting who they really are, unicorns are different. For their magic to work, they need to understand who they are. If a unicorn forgets what they truly believe in, their magic can often cease to function. Getting this magic back can often be similar to getting a cutie mark; they need to realise their full potential. This usually entails finding something that reminds them of themselves, and this can mean going on a quest to find such a thing."

Twilight closed the book.

She knew that time was running out for Luna. If the Princess didn't get her magic back soon, then the consequences would affect everypony in Equestria!

She hurriedly wrote a reply to her mentor's letter.

"Spike! Spike!" she called.

"What do you want?" asked her assistant blearily, "I was having such a nice dream!"

"I need you to send this letter right now!"

"Okay, okay!

Spike took the scroll and blew his green flames onto it. He looked questioningly at Twilight.

"It was important, Spike. Very important." Next Chapter: Setting Out Estimated time remaining: 21 Minutes