It had taken the better part of a day for the schoolponies of Ponyville and Spike to set up Scootaloo's complicated plan to freeze Ponyville. Nopony really understood what she was doing or where she was coming from.
"So Spike's going to evaporate this with his fire," Scootaloo explained, "which is going to create an air current over this, which will...no! Don't put that there, it needs to be over here! Hey, careful with that rainbow! If you stir it up too much, it'll lose potency! We need that for Snips and Snails to give us the final boost!"
Apple Bloom scratched her head. "Scoots? You sure you know what you're doin'?"
"Honestly? I'm making this up as I go," Scootaloo admitted. "But I'm pretty sure if we get this set up just right, we can make a cold enough air current that we can use our Trinity magic to—"
"But how are we going to do that?" Sweetie Belle asked. "It takes us forever just to get a reaction!"
"Yeah, but it's different this time," Scootaloo said with determination.
"How so?" Silver Spoon asked.
"This time, we're doin' it to save Ponyville," Scootaloo said grimly. "We gotta get it right, there's no other way."
"Yeah, well you'd better," Snips said as he trotted up hauling a wagon of ice sheets. "It's gettin' worse!"
"There's like four different marches goin' on, eh," Snails said as he stacked hay bales in two rows while Snips laid out the ice sheets between them, forming a long path of ice leading from the schoolhouse into Ponyville. "Some of 'em are yellin' pretty nasty things at each other."
"The hospital's stopped taking patients," Diamond Tiara reported as she ran up breathlessly. "They're rejecting Ponyville's current health care system—"
"No more updates on what's going on in town!" Scootaloo declared. "We need to focus!"
While Diamond Tiara and Silver Spoon took over directing the other fillies and colts in their preparations, the Crusaders turned their attention to synchronizing their magic.
Once Luna raised the moon, they were ready. "Now," Scootaloo said.
Spike blew fire over the ice corridor, creating a cold breeze as the ice began to melt. Fillies stood by with buckets to extinguish the hay as it burst into flames. The young pegasi collected the steam from the melting ice and spun it into clouds, which they pushed along on the breeze. Crystals of ice formed in the tiny little clouds.
"NOW!" Diamond Tiara yelled as the clouds reached the end of the ice corridor. Snips and Snails chugged huge jars of liquid rainbow, then dunked their heads into massive washtubs full of cold water. Steam billowed from the tubs, gathering into the clouds and expanding them as they picked up speed. The pegasi added their own power to the breeze, boosting it marginally.
The Crusaders closed their eyes and touched hooves. The Trinity Gems lit up brilliantly. The three of them rose into the air, sparks of pink and purple magic swirling around them as their Cutie Marks lit up like stars. A miniature tornado spun up around the fillies, forcing their classmates to back away, shielding their eyes from both the glare and the swirling dust particles in the air.
A shrill, piercing chime rang out into the night, echoing across the land. With a near-blinding flash, a massive, ghostly shape made of pink smoke and purple light surrounded the three fillies. At first an indistinct, blurry heart, it slowly took the shape of a phantasmal alicorn without a face, wings spread wide and head bowed low.
Another shrill chime rang out, and a humming, strobing column of pink light rose from the ground, coursing up through the Crusaders, their gems flashing in time with the thick rings of pink light that climbed the column and fed into the spectral alicorn, who grew brighter and brighter by the second. Then, as the light become intolerable to look at, it exploded outward in a ring of magical force that ripped through Ponyville and its environs in a magical shockwave.
The piercing chime and humming of powerful magic died out instantly, replaced by the sharp crackle of ice forming. The Crusaders dropped to their hooves, the Trinity Gems dimming and slowing their pulses until they went completely dark. The three fillies opened their eyes and looked around.
"Whoa," Sweetie Belle breathed.
All around them, their classmates stared in awe even as they shivered, for a patina of frost had formed over each pony's coat. A shivering Spike slowly made the rounds, gently breathing warm enough air in bursts over the ponies to let the frost begin to thaw without leaving them all damp, sodden messes.
The ground in every direction was encrusted in a thick, sparkly layer of crystalline frost.
"It...it worked?" Apple Bloom asked, blinking rapidly.
"It worked," Scootaloo said in a wondering tone. "It worked!" She jumped up, her wings buzzing excitedly. "We did it!"
"Mmm, you certainly did something, my little ponies," a regal voice said. "Though I would be most curious to learn what you have done."
The crowd of schoolponies gasped as Princess Luna descended into their midst, looking around at the frosty ground. Her hooves crunched on the frosted grass as she folded her wings at her side. She frowned slightly. "Most curious. It is spring, and yet Ponyville remains in the grasp of winter."
"Umm...we did that," Scootaloo said. "We...we kinda used our Trinity Magic to flash-freeze Ponyville."
Luna tilted her head. "Oh? And why, pray tell, would you do such a thing?"
"They had to do it to thave our town from the polly tickth!" Twist cried.
"It was a nightmare, Princess Luna!" Pipsqueak added. "Everypony was fighting and arguing and yelling and none of us were being cared for or fed or played with or anything!"
"More importantly, Ponyville's shops and services were all shut down," Diamond Tiara added. "Even Princess Twilight was affected!"
Luna nodded. "Ah yes, my sister warned me of these polly ticks," she said. "Polly ticks are serious business. Yet I do not understand what an infestation of parasites has to do with manipulating the weather in such a drastic and potentially destructive manner."
"The only way to get rid of polly ticks is to wait for them to die off in the winter cold," Spike explained. "Scootaloo figured if we could make Ponyville freeze over for just one night, it'd—"
"And she was right," a new voice interjected.
Princess Twilight Sparkle glided into their midst, looking battered and bruised, but grateful and proud. She landed beside Scootaloo and mussed her mane affectionately. "Thank you," she said. She looked around the schoolyard. "Thank you all," she added. "This plan of yours may have been dangerous and could have done serious damage to Ponyville, but your gambit paid off."
One by one, Twilight's friends showed up. They all looked harassed, abused, rather embarrassed, and quite damp...but also proud.
"Y'all saved us," Applejack said. "Ah couldn't be prouder."
"You flash-froze Ponyville without even being able to fly!" Rainbow Dash cried. "That is awesome!"
"I don't think we should be praising how they did it," Fluttershy said mildly, "because one night of unseasonable weather can do a lot of harm to plants and animals..." She smiled. "But I am proud of you all for finding a way to save Ponyville all by yourselves."
"I only wish I had been lucid enough to witness this," Rarity said. "We all saw the light in the sky, but the spectacle was over with by the time the polly ticks died."
"Speaking of which," Fluttershy said with a concerned tone, "we all need thorough bathing to kill their eggs, or we'll have to go through all of this again."
"Yeah, and then we'll have to check every crop in Ponyville for frost damage," Applejack said with a grimace. "Ah mean, Ah reckon it coulda been worse if'n we'd been stuck with them ticks, but—"
"Applejack? We'll worry about that," Apple Bloom said. "And the cleanup." She looked around at her friends. "Right?"
"RIGHT!" the schoolponies all shouted.
Luna chuckled. "You won't do it alone," she said. "I shall return to Canterlot and dispatch assistance for the cleanup and the crop survey. And anything else you require."
"Actually, if you could ask Celestia to come help me set up a bunch of giant washtubs," Twilight said, "that'd be great. It's gonna take days to decontaminate everypony in Ponyville after all this, but it'll go a lot faster if we have some really big tubs."
Luna nodded. "I shall alert her at once."
"I'll go get the Wonderbolts to come help us fill the baths," Rainbow Dash said, shooting off into the sky.
"Somepony should go find Zecora and get her to help mix up the special shampoo we'll need," Fluttershy offered.
"I'll do it!" Pinkie said cheerfully, zipping off in the direction of the Everfree Forest.
As the ponies dispersed to their various tasks and Luna flew off toward Canterlot, Twilight approached the Crusaders. "That was quick thinking, girls," she said. "And that was a huge leap forward in learning to control your Trinity Magic."
"Thanks..." Scootaloo yawned. "Twilight."
"It was..." Apple Bloom yawned. "Least we could..."
The three fillies collapsed in a snoring pile in the frosty grass. Twilight smiled and ruffled their manes affectionately.