The rest of Scootaloo's time in Cloudsdale flew by swiftly. Every day was packed with new experiences and hours on end of learning everything from making breezes to skimming rainbows to introductory frost formation. She had been surprised to learn that frost served an important role in protecting Equestria's crops and foliage from the bitter winter chill.
Curiously, nopony had seen Rainbow Dash for over a week by the time Scootaloo's training was coming to a close. There were also some curious stirrings about pegasi going missing; the last communication from Ponyville had simply been a date and time for Scootaloo to be at the balloon dock, and that had been ten days after her arrival in Cloudsdale.
At last, the day came to bid farewell to her hosts and return to Ponyville. When the Twinkling Balloon arrived at the dock, however, it contained four very tense and anxious fillies, and there wasn't an adult pony to be found.
"Hey Scootaloo," Apple Bloom said glumly.
"Hey girls," Scootaloo said, tilting her head. "What's wrong?"
The fillies looked at each other. "W-well..." Sweetie Belle began.
"Ponyville's...sort of in trouble," Silver Spoon said.
"Right now...right now, us little ponies are pretty much on our own," Diamond Tiara said. "Even the Princess is..."
"It's a mess down there," Apple Bloom said with a grimace. "Jes'...be ready. It ain't purty."
Scootaloo's ears pinned back as she climbed into the basket. "It...it isn't a monster invasion, is it? Or...or another Tirek or Discord or something?"
"Nah, it ain't nothin' like that," Apple Bloom said as Silver Spoon and Diamond Tiara began piloting the balloon back to Ponyville. "It's jes', well..." She looked at the others, then sighed and reached into her saddlebag, pulling out a little glass bottle and a magnifying glass. Sweetie Belle used her magic to steady them so Scootaloo could see.
Inside the bottle were two fat, ugly, spidery ticks with long, sharp-tipped legs, serrated mouth-parts, and sharp, bristly hairs. One of them was red; the other was blue. "What in the world...?" Scootaloo asked.
"According to Equestria's Best Pest Digest, they're called polly ticks," Sweetie Belle said. "Every single adult pony in Ponyville is infested."
"They even got Zecora when we went t' her fer help," Apple Bloom said miserably. "Right now, it's only us little ponies an' Spike that're safe."
"Some ponies from Cloudsdale came looking for Rainbow Dash and they got infested too," Sweetie Belle said. "We had to...we had to get creative to stop them from flying away."
"Not that they're in much of a hurry t' go anywhere," Apple Bloom muttered.
"We can't even send for help from Canterlot," Silver Spoon said miserably. "If one of the Princesses came to Ponyville, they'd end up infested too."
Scootaloo's eyes widened in alarm. "But...! Is everypony okay? They're not..." She looked at the polly ticks with alarm. "They're not...deadly or anything, are they?"
"Well..." Apple Bloom drawled, scratching her muzzle. "It ain't so much th' ticks as it is..." She looked at the others, who looked away.
"It's the way they're making everypony turn on each other," Sweetie Belle said miserably.
"Yeah, Ponyville's gone from peaceful and friendly to mean and shouty," Diamond Tiara said.
Scootaloo's muzzle crinkled. "I don't understand."
"You will," the others said resignedly...
* * * * *
"NO, dangit!" Applejack snarled, stomping a hoof. "Ah'm tellin' ya that there tax ain't gonna do nopony no good an' it's gonna hurt all us hard-workin' farm ponies!"
"Oh, puh-lease," Octavia scoffed. "Ponyville simply must raise taxes that will cover the cost of all the emergency repairs from rampaging monsters and other shenanigans!"
"We should make the PRINCESS pay for those repairs!" Golden Harvest snapped. "After all, most of those damages are her fault somehow!"
"I'm telling you, the sales tax in Ponyville is too high!"
"And I'm telling you the sales tax is not high enough!"
The five fillies wandered through clusters of arguing ponies. "What's going on here?" Scootaloo asked, wide-eyed.
"Polly ticks," Sweetie Belle said as she watched Rarity and Berry Punch bicker.
"When has Mayor Mare ever done her job right?" Amethyst Star shouted through a megaphone. "It's time for change! It's time we reform our local town government and give Princess Twilight complete oversight of Ponyville!"
Several ponies cheered. Several more booed. One stallion stood up and shouted, "WE NEED REPRESENTATION, NOT ROYAL MANDATES!"
"TWILIGHT IS A FAIR AND JUST PRINCESS!"
"TWILIGHT IS A NEUROTIC FREAKSHOW WITH TOO MUCH POWER AND NOT ENOUGH SENSE!"
The fillies watched as the mob degenerated into uncontrolled violence, blood and dust flying from the crowd of fighting ponies.
"Come on, let's go to the schoolhouse," Silver Spoon insisted. "It's the only safe place right now."
As they trotted through town, Scootaloo watched, horrified, as ponies who were lifelong friends argued over the most ridiculous things. "How did this happen?" she asked.
"Like we said, it's polly ticks," Sweetie Belle said as they reached the schoolhouse. All the town's fillies and colts were crowded inside; there wasn't a single adult pony present.
"There you girls are!" Spike bustled over to them. "You picked up Scootaloo, huh?"
"Yeah," Apple Bloom said.
"Good, maybe you three can fix this," Spike said as he padded over to one of Twilight's saddlebags, which lay against Cheerilee's podium, and fished out the peytrals with the Trinity Gems.
"Uhh...how?" Scootaloo asked as Sweetie Belle fastened the gems around their necks with her magic.
"Honestly, I have no idea, but it's just about the last hope we've got," Spike said. "I wrote Princess Celestia for help, but she basically quarantined Ponyville. It seems these polly ticks nearly destroyed Equestria hundreds of years ago, and only young ponies are immune to them." He frowned. "Well, and dragons."
"So how'd they get rid of them last time?" Sweetie Belle asked.
"According to the Princess, they died off on their own when winter came," Spike said. "Couldn't stand the cold. By Hearth's Warming, the polly ticks were gone and everypony was back to normal."
Apple Bloom frowned. "But...it's the middle of spring," she said.
"I don't think Ponyville can last until winter!" Silver Spoon cried.
"Can't we get Fluttershy to ask Discord to—"
"Wouldn't work," Apple Bloom said with a sigh. "They've spent the last four days arguing about who's Best Princess. Fluttershy's animals aren't even getting fed anymore."
"Well then what are we supposed to do?" Silver Spoon whined. Around the room, several other young ponies whimpered and whispered.
Scootaloo frowned, stroking her muzzle thoughtfully. "The polly ticks can't take the cold, right?" She looked around. "It doesn't have to be winter, it just has to be cold."
Her friends looked at each other. "Well...yeah, Ah guess," Apple Bloom said.
Scootaloo began pacing. "I learned a lot about air currents and temperature fluctuation this past week," she said. "I also learned how to make frost. It's all about how cold the air is and how warm the surface is and..." She waved a hoof. "I can't explain it, but I know how it works."
"Whut're you gittin' at?" Apple Bloom asked slowly.
"Well what if we can make Ponyville cold enough so frost forms on the ground? Just for a little bit?" Scootaloo suggested. "Just long enough to get rid of the polly ticks, then the weather patrol can fix things."
The others looked at each other, frowning. "But...how do we do that?" Sweetie Belle asked.
Scootaloo looked around the room, brow furrowing. "I think..." she said slowly. "I think we're gonna need every pegasus pony here, plus Spike's dragon fire, and..." She glanced at her two friends. "Okay, we know how to synchronize with Apple Bloom's magic, but we couldn't get in synch with mine and we haven't even tried with Sweetie Belle yet, but..." She took a deep breath. "I think...if we're gonna save Ponyville, we need to get in synch, and fast.
"Because we're gonna need to flash-freeze Ponyville, and the only way that's gonna work is if we can use Trinity Magic."