Karyn gleefully danced around her room. Thus far, everything was perfect. Only one week home, her room hadn’t had the chance to get messy, and to make it better, her parents had gone out for breakfast and hadn’t asked to come along. She had perfect leave to wait for Derpy and begin a day of fun together.

Since Derpy was coming the long way, Karyn left the window open and seated herself in front of her makeup mirror. When she heard the whoosh of air and the sound of hooves on carpet, she turned and closed the curtains.

Derpy Hooves appeared, a scowl etched on her face.

“What’s the matter?”

“Stupid wings,” said Derpy. “Stupid magical ability to fly and walk on clouds and stuff.”

“Hey, don’t say stuff like that. Being a pegasus is really cool. And if something went wrong, we’ll figure it out together.”

“Nothing’s gone wrong yet. It’s that it will go wrong. Here I am on Earth, ready to spend time with my friend. Does that get me out of tornado duty? You would think it would, wouldn’t you?”

Karyn searched her memory. “Tornado duty? Oh! You mean getting the water up to Cloudsdale.”

“Yeah. Flying around in a circle with nothing to look at but the flank of the pony in front of me.”

“And they won’t let you out of it?”

“Right,” said Derpy. “They say it would be a bad precedent. They could do it without me, but if I get let off, then everypony else is going to want off. Which I can kind of understand. I just don’t like it.”

“I guess I’d better pack my bags for Equestria. I honestly wouldn’t mind watching, if it can be done safely.”

“Having you around will be nice.”

Karyn mounted Derpy, and she took to the air.

Their descent in Equestria was slow and deliberate. Karyn didn’t know if that was Derpy saving her strength for the task to come, or just not wanting to get there, hopefully to procrastinate. Karyn tried to commiserate.

“It does suck that there’s this extra duty that only pegasi have to do.”

“That’s what I’m saying!”

“I mean it’s not like the Earth ponies have to get together once a year and cause an earthquake to make sure there’s enough dirt in Equestria, right?”

Derpy paused, and Karyn wondered if that might not be the case after all. But then she said, “No, of course not. They have to farm, of course, but everypony owns their own farm. They don’t get together on, say, Applejack’s schedule and do it then.”

“And the unicorns don’t have to all point their horns in the same direction and cast a giant spell in order to make sure all the ponies’ brains don’t shut down.”

“Almost certainly not!”

Karyn squinted. “Do they have any kind of special duty that’s equivalent to your tornado?”

“Hmm, let me think. They do have to go occasionally and restore the spell that keeps the Everfree Forest at bay. But that only takes a week of intense concentration!”

“Really?”

“Yeah!” said Derpy. “And sure, the Earth ponies have to get together each year and rebuild the retaining walls that keep the rivers from overflowing, but that’s just backbreaking labor. None of those duties make anypony miss their Sunday with Karyn!”

At this point, Karyn was no longer to figure out if Derpy was joking or serious. She also wasn’t sure, if Derpy was serious, that she didn’t still disagree that they were both being hard done by. She decided to forget about it and enjoy the ride.

Derpy flew in a new direction from any that Karyn had gone before. From the angle of the sun and the time of day, Karyn judged it to be generally northeast. Her thought was confirmed when she saw the clouds surrounding the mountains of Canterlot off to her left.

The flight was one of the more relaxing ones that she’d had, and vague memories of the times when she was frightened to fly on the back of a pegasus arose. Now, she felt only the awkwardness of being on top of Derpy. It was like having a friend who always pays for everything.

To either side, she noticed other pegasi flying in the same direction. They were not going full speed, so Karyn concluded that they were told to build up their energy for the task ahead. Still, it was a little thrilling, as the sky filled with ponies. If any of them noticed Derpy carrying a rider, they didn’t say anything. Karyn felt part of the flock.

Derpy descended toward the reservoir. True to Equestrian nature, it was indistinguishable from a large pond or a small lake. No sign of a concrete base or a dam could be seen, and Karyn could only conclude that rainwater collected in the depression. She asked Derpy about it.

“There are a bunch of reservoirs all over Equestria, and the weather ponies rotate which ones they use. They pick places where fish don’t go. There’s no good in taking water that something’s living in.”

“That makes sense,” said Karyn. “but how do they get filled in the first place? I mean, there’s no point to making it rain over the reservoirs when you’re only going to tornado it up anyway.”

Derpy thought about that. “I don’t know. A little rain gets into them, but it shouldn’t be enough to fill them. I wonder…”

“What?”

“Well, the water that the pegasi use for rain and snow goes into the ground, right? And then the Earth ponies use it to grow plants. And then ponies eat the plants, or they just drink the water. And after we eat and drink…”

Karyn cut her off. “I bet the unicorns just use replication spells on the water. That’s probably it. No reason to question it further.”

Derpy came to a landing at the edge of the reservoir. The ground was spongy and soft to Karyn’s feet. Many pegasi were already there, stretching their wings and their limbs, but a few more were landing.

“I have to go sign in,” said Derpy. “I’ll be right back.”

Seeing all the wings, and the sheer force of flight power put an idea in Karyn’s head. As soon as Derpy returned, she said, “What if I use my changeling powers to make myself a pegasus pony? Then I could fly with the rest of you.”

“You really want to do that?”

“Sure!”

Derpy looked around. “Let’s find a private spot to try it. We don’t want to freak everypony out by showing off changeling magic.”

Finding seclusion was not easy with the mass of ponies milling around the reservoir, but Derpy was happy for any excuse to get away, and they found a small hill a short flight away. Once there, Karyn concentrated and watched the green light flare up around her.

The pegasus that she had transformed into was flesh-toned and had a mane the same blonde as Karyn’s hair. She looked very much like a human-pony hybrid, but to the native Equestrians she would seem quite exotic.

“OK, here I go.” Karyn spread her wings and leaped into the air, but a half-second later braced her hooves on the ground. “That didn’t work.”

“What’s wrong?”

“I’m not sure. Let me see if I can take off from the ground.”

She flapped her wings, but achieved nothing other than a slight movement of air.

“You can’t fly?”

“It seems not. I mean, I’m just guessing here, but pegasi don’t fly by physics. They need magic to do it. Pegasus magic isn’t changeling magic, and that’s all I have. Changelings are lighter and might be able to fly just on aerodynamics. So the queen couldn’t give me flight.

Derpy was disappointed. “Oh, well. You can just watch. Let’s get back to the water.”

They trotted to the reservoir. Karyn kept her pegasus form. Even if it didn’t render her able to fly, it reduced the stares that other ponies gave her.

Derpy got in line with the other pegasi and started warm-up exercises. It reminded Karyn of the “squad lines” that she had in her physical education classes. Just as in there, not everyone kept the same pace. Derpy in particular was lagging behind. Halfway through, she gave up on the warm-ups and just stretched her wings.

“You’re not going to be able to keep up with the other ponies,” Karyn said.

“Once the tornado gets going, everypony will be in everypony else’s wake. It’ll work out. I don’t intend to work any harder than I have to.”

Karyn realized that the one frame of reference she had for the tornado event was when Rainbow Dash had organized it for Ponyville, and that she was far more intense than anypony present. To Derpy and the others, this was just community service, not a chance to break records or make a name for themselves.

As if to underscore this point, the flight leader came up and pointed ponies into lining up. Instead of barking orders, she asked them nicely and went from group to group.

When she came up to Derpy, she said, “Hi, I’m Misty Showers, I’m coordinating today’s tornado. Name?”

“Derpy Hooves.”

“And you are?”

“Oh, she’s not participating,” said Derpy with a little envy. “She’s in no condition to fly.”

“I see. All right.”

She moved on to the next group with her clipboard. Derpy waited until she was out of earshot, then said, “I can see the fun in telling folks the truth but not the whole truth.”

“Right, but she took that a lot better than I thought she would. If ponies try to skive off this duty, you would think she’d double-check everypony.”

“I wonder if I could have made the same excuse. Too late now. You’d better get far away so you don’t get swept up. Here, hold my saddlebags until we’re done, please.”

Karyn trotted to the same hill where she had transformed to get a good look at the proceedings. Instead of going behind it, she sat on her haunches atop the crest. It gave her a perfect angle to see the reservoir.

It was also, she reflected, the first chance she had taken to really explore what it was like to use her powers to change form. Her fully-made-up disguise didn’t feel any different from when she actually took the time and effort to make herself pretty. But being a pegasus pony was different.

Even though she couldn’t see her hands, and couldn’t use them either, she didn’t have proper hooves. They were, as best as she could think of it, the size, shape, and color of hooves without actually being them. If she disguised herself as an Earth pony, she wouldn’t trust herself to kick without getting hurt, the way Applejack could.

But a visual illusion still had its advantages, as nopony stared while they got into position. Misty ran from here to there setting them all into exact positions. Then she stood outside and blew a whistle. The pegasi took off, but a moment later, she blew a double-blast on the whistle, and they all stopped.

“I wonder why?” said Karyn, and figured that unless they all took off at about the same acceleration, they would bump into each other. It was like trying to merge on the highway.

It took two more tries before they all got off the ground and there was no abort signal given. Karyn scanned the wall of ponies and spotted Derpy. She was doing just as she said she would, zoning out and letting the course drive her. Each time she travelled around the far side, Karyn had to pick her up again a moment later.

“My eyes are going to match hers if I have to do this for very long,” Karyn said to herself.

It took a while for her to see the evidence of the tornado. They weren’t actually moving any black clouds, so it lacked the classic funnel shape, but a few specks of dirt and debris got caught up and spun around. Karyn could tell how much speed and power they were generating by how fast the dirt whipped around, and she understood the need for goggles.

Still tracking Derpy, Karyn saw the angle of her wings dip in toward the reservoir, and the water responded by forming a hump in the center. Leaning forward on her hooves, Karyn waited for the moment when it would shoot up into the sky. She was so engrossed in the proceeding that she didn’t notice the other pony watching from a point about ninety degrees away on the circle. But he flew toward her rapidly.

“You! Pony! What do you think you’re doing out here?! You should be in there with the rest of them!”

Karyn thought that it would be easy to explain. “No, you see, I’m not really a p—“

“This is my little sister’s first time running the tornado, and I will not have anypony sitting on the sidelines for it. You will get your flank into that formation immediately or so help me I will tan your hide!”

“You don’t understand. Your sister—Misty?—she came over to my friend Derpy and me, and Derpy told her that she was ready to go, but that I wasn’t signed up, and that’s true, because I’m actually a human from another world, only obviously I don’t look like one, but that’s because I’m also part changeling, which is itself a long story, and you don’t want to hear it, but—“

She realized that she was rambling, and the pony just kept steaming at her. “That’s the sorriest made-up excuse I’ve heard. Are you going to get in that tornado?”

Karyn decided that the only sensible course of action was to drop her disguise and show him that she was in no way a flyer. So flustered was she by his anger, though, that it took a moment before she could bring up the muscle memory needed of how to shapeshift back. To the stallion, it must have looked like she was staring blankly at him.

Just as the green light surrounded her, the stallion took off and flew towards her, his front hooves outstretched. He grabbed her around the waist and started flying toward the tornado. “Get. To. Work!” he shouted as he hurled her in.

Karyn hoped that, even if she couldn’t fly, her wings would provide some kind of lift that would at least cushion the fall. She focused on getting her hooves down underneath her so that she could tuck and roll. She wasn’t very high above the water, maybe only twenty-five feet, so she wasn’t scared for her life, but she knew she still risked injury, and had the natural adrenalin rush that anyone gets from falling.

She mentally congratulated herself for being so rational in the moment, figuring that the reaction was making her brain work overtime out of survival instinct. She also found that she was not falling as fast as she should have. The wind from the tornado was buffeting her and she was now whipped like a leaf rather than falling.

If the pegasus stallion had watched to see that she had gone into formation, Karyn couldn’t see, and so as far as she knew nopony else knew she was in the tornado.

Still in her hyper-speed perception mode, Karyn felt herself no longer just slowed in her fall, but lifted up. It reminded her of some of the thrill rides she had been on at amusement parks, the straight up-and-down verticals that let the rider experience the sensation of free fall.

With the ground approaching rapidly, and still in desperation mode, Karyn reached for the saddlebag that she still had draped over her. She tore it open and pulled out the first spell she could find, hoping it would be the time-stop spell or a strengthening spell or something to help. She slammed it on her hoof and turned, but there was no visible reaction.

Meanwhile, while lazily flying in the tornado, Derpy had not seen Karyn, but had heard her scream. Ignoring any effect it would have on her duty, she broke formation and flew for the direction she heard the screaming from. That took her on an arc through the circle, and several other ponies had to pull up short. Down at the reservoir, the bulging water wavered and sank back. The tornado was coming apart.

None of that mattered to Derpy, though. She knew nothing about the pegasus stallion and thought that perhaps Karyn had tried to fly again. With her crooked eyes she could see both Karyn and the ground, and they were getting disturbingly close to one another.

Using all of the energy that she didn’t put into the tornado, Derpy pumped her wings and flew faster, but her estimates still put her too late to catch Karyn. She decided to go for broke, straightening out into a full dive. It would be difficult for even an experienced flyer to pull out of it, and for somepony who never flew more than enough to bring mail from one house to another, it was suicidal folly. Derpy didn’t care. If all she could accomplish was to crash together, it was enough.

There was a crash, but not of hooves and grass together. A low rumbling explosion seemed to propel Derpy, now with Karyn’s body in her hooves, back toward the sky and away from danger. For some reason, neither the added weight nor the force of gravity seemed to be impeding her, and it wasn’t until she’d gone about half a mile up that Derpy finally felt ready to slow down.

She pulled up and said to Karyn, “You OK?”

“I think so.”

“Can you change back to human? Your weight is the same, but it’s easier if you’re on my back and I don’t know how to carry you in this form.”

Karyn was still shaking, but said, “I think so.” She concentrated, and this time the green light surrounded her completely. She was back in her own body.

As Derpy maneuvered her around, she turned to see the path they had come. From almost the ground was a fading light of gray and yellow. “Whoa. What’s that?”

Karyn turned her head to look, but since Derpy was turning her body also, she had to keep moving to see the light. At the bottom, where they had nearly hit the ground, the grass was blown away and the earth was colored gray as well.

She had an idea. “What exactly happened before you picked me up?”

“Well, I heard you screaming and saw you falling, and I’m really not sure what I did. I just dove for you. It was hard flying at that speed, but then I pulled up and it was like I was flying through nothing at all.”

“Mm-hm. I think you just pulled off a Sonic Derpboom!”

“A what? There’s no such thing.”

Before Karyn could give her any further answer, Misty Shadows came flying up. “Oh, my Celestia. Are you all right?”

“Yes,” said Derpy. “I’m sorry I wrecked your tornado. I’ll start it up again, and I’ll really fly hard this time.”

“You didn’t see? Take a look!”

Karyn and Derpy turned to the reservoir and watched, wide-eyed, as the water was floating up toward Cloudsdale. But instead of the funnel shape it normally took, the water had formed itself into seven huge bubbles and was maintaining formation as it rose.

“OK. Maybe there is such a thing as a Sonic Derpboom.”

“That was cool!” said Misty. “Next year, we won’t even need the tornado; we can just have you do that!”

“No way! You’re not throwing Karyn around just to get your water lifted.”

“You can’t do it unless there’s a life-or-death situation? That’s a shame.” Misty watched the bubbles as they faded away. “Come to think of it, why was she falling?”

Karyn recounted the incident with the stallion. She tried to be as nice as possible, but Misty’s eyes got wider as she listened. Finally, she shouted, “Stormy!”

The stallion flew up, seemingly not aware. Karyn just looked at Derpy. “Stormy Showers? Kind of redundant, no?”

Derpy shrugged.

Meanwhile, Misty was chewing out her brother in front of all the pegasi who had helped. “So next time you think you can help, why don’t you just butt out?! You always do this, any time I have something going on, you have to stick your muzzle in.”

“I was just trying to make sure that your first tornado went smoothly.”

“And instead you nearly killed somepony! Not to mention that the tornado fell apart. You are going to write my report and then you are going to appear before the weather council and explain what a doofus you are and—“

Derpy whispered to Karyn, “Let’s get out of here. It’s always embarrassing watching somepony get yelled at.”

Karyn agreed, and they turned away. “Well, I bet news of this will get around quickly. I wonder if that means that every pegasus can break the sound barrier.”

“Maybe only when someone’s in trouble falling. That wouldn’t be good.”

“Well, I hope that guy learns his lesson. And I guess I’d better be a little more careful turning into ponies.”

“It’s a shame you can’t fly, though,” said Derpy.

“Not really. I don’t want to get too powerful. This way it won’t go to my head.”

Author's Notes:

It's the preview! (Hey, you try coming up with new introductions each week!)

“That is fortunate,” said Derpy. “But what are you doing here?”

“Kind of planning ahead. See, last year we had that whole issue with going back to school and having a roommate and such.”

“Right, and we took care of that. Peony is waiting to fill your room again.”

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

"That woman has to have a kind heart to be able to make something so beautiful.”

“You really liked that?” asked Karyn.

“It reminded me of Cloudsdale. I haven’t been back in a long time, and although I hadn’t realized it until I saw that painting, I miss the clouds and the thin air."

That was the preview! (Hey, you try coming up with...)