One Year Later...
"How many casualties from the last skirmish?" Princess Celestia asked.
"Twenty-seven, Your Highness. The Empire doesn't appear to be taking prisoners anymore."
War had erupted in Equestria. The battalion of guards that had been sent to the Northern Tundra from Canterlot never arrived, all presumed to be killed alongside Shining Armor and Princess Cadance. They, Celestia often thought to herself, were the first of endless casualties in an endless war. Only a few days after the airship crash, King Sombra of the Crystal Empire declared war on Equestria. Though Celestia was in the midst of preparing for such an inevitability, she had still been caught off guard.
In the first few months of the war, Sombra cut a path right through the under-defended Equestrian countryside, capturing key settlements including Vanhoover, Rainbow Falls, and Hollow Shades. A failed siege on Cloudsdale was what eventually turned the tide in Equestria's favour. Now, Sombra's forces had been pushed back over the northern border into the tundra, but Celestia's forces were dropping significantly.
"Contact their families, Flash, have you managed to recover all the remains?" Celestia asked solemnly. She had long since stopped counting how many ponies had been lost in the fight against Sombra, it didn't hurt as much if she didn't think about it.
"Most of them, yes." Flash explained. Wartime meant that soldiers rose through the ranks faster than usual, and after only a year of service, the pegasus was now the captain of Celestia's most elite legion of soldiers.
"Ensure they are all sent back to their homes."
"Of course, Your Highness."
Flash left for his tent to write another set of condolence letters. Celestia took a few moments to watch the goings-on of the encampment. Many were stationed around the border area between Equestria and the Crystal Empire. Soldiers who had just returned from battle lined up at a tent to collect their dinner. Medics carried injured ponies into the infirmary tent to tend to their wounds.
It was a cold evening. A quick spell would immediately blanket the encampment in warmth, but magic was only allowed to be used in short bursts in the most necessary of circumstances. Sombra could easily pick up the energy emitted from a single powerful spell and find the camp's location. For the most part, only the unicorn medics were allowed to use magic to tend to life-threatening injuries with no other options.
The sun had reached its usual place in the western sky where it waited for Celestia to bring it beneath the horizon. Controlling the sun and moon was a duty Celestia had been performing for over a thousand years, and even a war couldn't stand in the way of this. The alicorn took off into the sky to look for a secluded spot where she could bring Equestria from day to night without alerting Sombra to the whereabouts of her camp.
After landing on a secluded hilltop, Celestia had an expansive view of the tundra below. Before the war, Celestia had rarely travelled this far north. Even before Sombra's rise to power, when Equestria and the Crystal Empire were close allies, she had only been to the Empire twice. The first was a diplomatic visit not long after her and Luna's coronation. The second was to confront King Sombra, which ended in the Empire disappearing. Celestia was sure that the rolling snowy hills of arctic north were once beautiful, but these days they were scarred by an unforgiving war, alongside the dark crystals formed by Sombra's growing magic.
As Celestia used her magic to lower the sun to its rest, she turned her attention to raising the moon. Darkness fell over the tundra as the Mare in the Moon's gaze was lifted into the night sky. A sight that pained Celestia each night.
"Oh, Luna." the alicorn whispered to herself. "I wish you could be here by my side. Perhaps together we could have already stopped this evil by now."
Composing herself, Celestia took off to return to the base camp. Lowering the sun was a feat that required much magical energy, which Sombra would be able to sense. No doubt Crystal Empire scouts were already on their way to her location. She would not be there when they arrived.
Celestia had anticipated King Sombra to attack almost immediately after the Empire's return, but even still, Equestria was caught off guard by the Crystal Empire's initial assault. Equestria's northern border was guarded only by a small patrol group at the time, and Sombra's forces had wiped them all out before they could even warn Canterlot of the coming invasion.
Underpowered, Celestia was forced to draft in all existing guard reserves in order to have even the slightest chance of holding Sombra back from taking the capital. The Wonderbolts, Equestria's most famed flight acrobatics group, were also quickly pulled into the war to serve as the army's air cavalry group. Even with the reserves drafted in, the Wonderbolts were a small squad, but were known across the war front as an efficient team.
One such reserve drafted into the war was Rainbow Dash. She had idolised the Wonderbolts as a young filly growing up in Cloudsdale, and once she grew older her skills in flight led her to be accepted into the Wonderbolts Reserves. Rainbow Dash's dream of flying with her heroes was realised sooner than expected, but not in a war she had ever imagined.
"Commander Dash. Permission to enter." spoke Fleetfoot from outside the Wonderbolts' tent.
"Permission granted, Lieutenant." Rainbow answered. She looked up from her work to greet her second-in-command.
The past year at war hadn't been kind to Rainbow Dash. Frequent skirmishes against Sombra's forces had cost the pegasus one of her wings, which was replaced by a prosthetic. Another particularly nasty encounter had left a scar on her right eye.
"Commander, a letter has just arrived from Canterlot. It's from Spitfire."
"How is she?" Rainbow asked.
"Recovering well, though she says it's unlikely she'll return to the front anytime soon." Fleetfoot sighed. "The injuries to her legs mean that she needs to re-learn how to walk."
Rainbow gave a disappointed sigh. "That's a shame."
"She also asked that I pass on her congratulations on your promotion." Fleetfoot continued. "She couldn't have picked a better pony to fill her shoes herself."
"I appreciate her confidence in me." Rainbow smiled weakly. "As do I appreciate the Princess', but as the only veteran Wonderbolt left on the squad, don't you think you should have taken command?"
When the war began a year ago and the Wonderbolts were first drafted in, the squad consisted of five veteran members and six reservists. Four of the five veterans had since left the front, either through serious injury or by being killed in action. Spitfire, the original commander of the squad, was the latest to be evacuated only a week ago, leaving Fleetfoot as the only remaining pre-war Wonderbolt. She was the obvious choice, Rainbow thought, to take command of the team, but it seemed Celestia thought otherwise.
"I thought so too at first, to be completely honest, ma'am," Fleetfoot said. "But as this war's gone on I've learned that our superiors are saddled with difficult decisions all the time. I'm sure the Princess knew what she was doing by assigning you to the post."
"I hope so." Rainbow frowned. "We've come out lucky in the past few skirmishes, but Captain Flash has been talking about a direct siege on the Crystal Empire itself. I don't know if I can lead everyone into a battle like that."
"I think you're more than capable of leading us, ma'am." Fleetfoot smiled. "In fact-"
The mares were cut off by the sound of a horn outside the tent. A sound that always meant trouble.
"What's going on?" Rainbow asked as she and Fleetfoot exited the tent, equipping their helmets.
"Crystal Soldiers!" Flash announced. "Spotted just past the ridge. We need to hold them off while the injured are evacuated!"
The harsh blizzard that was coming down on the encampment had suddenly cleared. It was rumoured that Sombra's dark magic allowed him to manipulate the northern tundra's harsh climate, and now it seemed he had cleared the storm to allow his soldiers better visibility when attacking the camp.
Medics carried injured soldiers onto sledges that would carry them to a backup encampment at a new location. Now that they had been discovered, the sledges could be powered by magic for part of the journey, but with no wind, Rainbow was forced to delegate some of her pegasi to help bring the sledges the rest of the way.
"Thunderlane, Meadow Flower, go with the injured to help power the sledges. The rest of you, assume formation and get ready for the fight of your lives!" Rainbow commanded to her team.
Princess Celestia stood in the center of the encampment, raising a shield around it.
"My magic is weaker at night, as I'm sure Sombra is well aware. This shield won't hold long, so prepare yourselves!"