“It would help, Princess, if we knew when and from where Princess Celestia was banished” stated Spell Nexus “Perhaps there may be some residue we could collect that would give a lead as to what type of magic she used?”
Luna giggled, much to the consternation of the greybeard unicorns present. Had such a fatuous sounding response come from any of their students, they would have been given very short shrift indeed, but as their patron was Princess Luna, then things were by necessity a little different.
“My apologies good Sirs. Having thought this through, I believe the spell to have been cast on a cloud high above Canterlot. I can neither see you flying up to a cloud, nor the same cloud still being there, so I am sorry to advise that this avenue of enquiry will be fruitless.”
A ripple of understanding coursed through those present, one or two polite guffaws rising to counterpoint the absurdity of the situation.
“Very well then” said Spell Nexus “We shall proceed along the lines of the spell that were used to …um …”
“There is no need to be bashful about my past, dear friend” said Luna with a disarming smile “I assume you mean we should base our working on the branch of magic that was used to banish Nightmare Moon a thousand years ago. That does at least have the benefit of having been properly documented, I trust?”
“Yes Princess. We are, I believe, all familiar with that particular magic, are we not?” he said casting his eyes around to receive a volley of nods affirming his supposition. He continued, "Whilst it is acknowledged that all alicorns have the potential to cast a Banishment spell, it is the particular individual's experience and magical prowess that determine over what range it will be effective. You, for example, Princess, would be able to banish somepony clean out of Equestria and round the other side of the planet with ease, but significantly longer distances such as to the moon and even the sun can be expected to require some additional magical assistance."
From out of thin air, Spell Nexus summoned a board upon which he magically wrote a sequence of operations along with their associated incantations. Firstly he wrote down the original spell cast by Celestia that had involved the Elements of Harmony, and then alongside it he wrote a modern derivation of the spell that could be cast without the need for any artefacts. The sage old unicorn painstakingly created a step by step guide, noting comments and contributions from others as he progressed. It took some time, but eventually all unicorns present were happy that it should work. This revised version had the potential be cast anywhere, which was presumably therefore akin to the magic Chrysalis had used.
Spell Nexus ran through the two spells side by side, stroking his beard and nodding before announcing that he was satisfied. Next he magically extended the levitating board by one more panel and in a few intense minutes he had reversed the banishment spell, turning it into a releasing spell in a form that all could see and understand.
“Princess Luna; the spell is, as you can see, not especially demanding. However, …”
She always hated when somepony said “however” as it always implied a hidden catch that could foil even the simplest and best thought through of plans.
“… we are only unicorns; the finest unicorns in the kingdom, I grant you …” he added with his impish smile “… but unicorns nonetheless, and this requires us to work through you as the bearer of alicorn magic.”
Luna nodded. She had been expecting this.
“How long before you can start?” she asked tentatively.
“We’re ready when you are Princess” he said, his watery old eyes peering fixedly at her over his glasses.
“Very well. I am yours to command.”
“Good. I want you to focus your aura onto the sun and simply open a channel of magical energy without compromising it with any other thoughts. We will then fill that channel with the releasing spell and, if everything works according to plan, Princess Celestia will be returned to us.”
“And if it goes wrong?” she asked.
“We’ll cross that bridge if we get to it” he said breezily.
“Begin?” she asked.
“Begin” he confirmed.
Luna walked over into the sunshine and closed her eyes, lowering her head so that her horn pointed through the window. She stood with her legs apart and braced as she drew her thoughts into focus and conjured a blue aura to form around her horn. Once the aura had built up enough energy, a blue stream of magical power headed straight towards the sun.
Immediately, the other unicorns directed their power towards her and one by one she accepted their magic until she was awash with spell crafting energy. It felt like she was holding a hosepipe and somepony else had turned the tap on, the force of the water making it difficult to keep the aim on target, but she knew she had to for the sake of her sister.
An overwhelming vision of gold grew larger in her consciousness and she held on, maintaining her unfaltering aim for as long as she could until she was unable to keep her psychic lock any longer and was blasted backwards with the residual magical energy, falling over over unconscious.
She felt a gentle nuzzle bringing her round. A familiar voice, but she couldn’t place it.
“Lulu, Lulu darling, thank you” came the caring feminine voice “I love you little sister.”
“Sister?” she thought to herself “Then this must be …”
She struggled to open one eye; everything was a blur of large abstract colours, but there was some gold glinting against a white background and a familiar comforting smell.
“Celly … ?” she enquired, daring for a moment to believe that it was her sister next to her.
“Yes Lulu, you released me” said Celestia tenderly “I love you, little Sister.”
Struggling to bring the image in front of her into focus, Luna reached out and embraced her sister, totally unable to hold back the happy tears of their reunion. She buried her muzzle into the comforting soft white fur and held her tightly, sobbing with the purest delight, never wanting to let her go again. Celestia for her part gave up any pretence of maintaining her regal composure and wrapped an affectionate wing around Luna, allowing her own tears to run freely at the joy of her release thanks to her sister’s undeniable love.
“Sister” said Luna, struggling to compose herself “Our work is not yet done.”
"What is required from us?” asked Celestia, gently refurling her outstretched wing.
“The combined might of our Night Guard and the Royal Guard go to fight a changeling invasion force approaching from the Badlands. I believe that is where we should be, if you feel strong enough.”
“If our armies need us, then our position at their head” stated Celestia emphatically “Where is the shapeshifter Sunchaser?
“I have banished her” said Luna, then adding as an afterthought “But I am not sure where to.”
“So, she may have rejoined her army then?”
“Possibly, but I also have reason to believe that the members of her army have similar shapeshifting abilities, so we must be on our guard. I also do not know whether they are drawn from tribes with different abilities such as earth ponies, unicorns and pegasi, but consider it would be wisest to assume the worst.”
Celestia took this all in and called for the Clerk of the Court to have battle armour for her and Luna to be brought to the throne room immediately. As he sped off to do her bidding, she turned to thank Spell Nexus and the other unicorns present, remembering each by name and making sure that each knew how much she recognised and appreciated their contribution in helping bring about her safe return.
As she finished, two armourers accompanied by four young pages arrived at the doors to the throne room carrying two sets of battle armour, one gold and the other black. She dismissed the unicorns and summoned the newly arrived party to enter, all of them looking a little surprised at being asked to dress the Princesses in the throne room instead of somewhere more traditionally appointed for the purpose. However, time was of the essence and neither Princess wanted to incur any more delays than was absolutely necessary.
Once they were both kitted out, each looked the other up and down.
“It is like old times, Sister” said Luna, with a proud smile forming on her face.
“Indeed” concurred Celestia “May we prevail once more.”
With this they strode out onto the balcony and Celestia sprang into the air followed half a wingbeat later by Luna.