Derpy woke up one day in her bed feeling sad, but that wasn't the interesting part of the story. Derpy felt sad some days, or most days, or when she thought about it at the end of the day she usually felt sad, and she couldn't remember many times during the day she had been happy, and if she did she didn't feel that they mattered very much.

The thing that was strange about today was that Derpy felt like something bad had happened. That wasn't unusual either, because pretty often she would dream about something that had happened a long time ago or felt like it had anyway but really hadn't. Somepony would always blame her for something, and no matter what she did, she couldn't make it right, and the feeling of screwing everything up forever and ever would stick with her until her eyes were open all the way and the blankets were all the way off, and sometimes even then until she took her shower, and then it went away for sure. Almost always, definitely.

It felt instead like something bad had happened in reverse. Something very bad was going to happen, and Derpy had already prepared for it, braced for it, and experienced it backwards. She watched the clock in her living room for a few minutes to make sure it was still ticking, and even then, all that determined was that her clock was ticking. It didn't mean time was moving for anypony else. Time was tricky that way.

Derpy ate her cereal and got ready for work. She put on her saddle-bag and her post-office hat that she got to take home with her as long as she promised to wash it and keep it clean and not to lose it, which she had only done once. Derpy liked the way she looked with her hat on, or with any hat on, though it did depend on the hat. Derpy liked hats. They made her look like somepony wearing a hat.

On the way to work, Derpy didn't notice anything unusual. She might have gone the entire day without noticing, if she hadn't somehow gotten stuck behind somepony when she was on her lunch break and going to retrieve her sandwich and cookies from her compartment in the employee room in the back. Somepony had been standing in the hallway taking up all the space, and Derpy had asked him politely to move. And he hadn't seemed to notice her, or say anything back, but he moved all the same. And even though Derpy got past him fine, and went on to eat her lunch in peace, by herself, as usual, she couldn't help but feel something was strange. Something about that pony was strange, she thought to herself. Chew chew. Her sandwich was good. She made it herself.

When Derpy was finished her shift, she waved and said goodbye to her co-workers at the front desk. They were busy, and none of them said goodbye or waved back to her, and normally she wouldn't have thought that was unusual either, except that she'd gone out of her way to be extra loud and wave a lot and make sure they would notice her. Only they hadn't noticed her. Derpy felt like chewing her lip on the way home, which was a bad habit she had from when she was a filly, but she managed not to do it. She liked the way it stung in her mouth and tasted a little bit like rain. But she didn't like the way she couldn't eat things very good for a few days after. That was why she always tried not to do it, and felt good when she succeeded.

When she failed, she felt awful.

Derpy stopped at a cloudy convenience store on the way home. She got a blue fizzy soda from the case at the back and a chocolate-chip-banana muffin from the case beside the coffee machine. When she brought them up to the counter, she made sure to smile extra hard, and she got her favorite question ready in her head, that she would always ask when she was out and she was brave, and not working, on account of which she'd already asked every pony on her route and in her office anyway.

Derpy's favorite question to ask was actually two questions, and both of them were about her dad's favorite band. First, had they heard of her dad's favorite band, and second, did they think they were the greatest band in all of Equestria?

This was difficult because Derpy didn't remember the name of her dad's favorite band, and he wasn't around to ask anymore. But usually whenever she asked somepony if they remembered the band with four ponies and a pun in their name, somepony did remember them, and they did like them. But they never thought they were the great band in all of Equestria. Derpy wondered why that was.

Today Derpy was ready to ask her question when she got up the counter. She started with:

"Hi! How's it going?"

But the pony at the counter didn't say anything.

He rung up her items. And he put them in a paper bag and handed it to her across the counter. But he never said a word.

When the next pony who was in line behind Derpy stepped up to the counter and said 'Hello', the shop-keeper said 'Hello' back. And then they started a conversation about the weather, which lead into sports, which lead into the fact that the pony buying taco fixings was heading home to his wife and two children, and was expecting to play with the kids later that night in the back-yard, throwing the ball around while they were on vacation from school.

Derpy learned all of this while standing next to the pony who had been behind her in line. She held her paper bag of things tight to her chest while she listened, feeling short of breath and a little light-headed. She stared at the two ponies the entire time they talked. When they'd finished, and the pony making his purchase left the store, Derpy got back in front of the counter. There was nopony else in line.

"Hey," she said. She waved her hoof in front of the glass screen that covered most of the counter space. "Hello. Did I do something wrong?"

The pony didn't say a word.

Derpy stood in front of the counter for about half a minute, staring down at the ground. She chewed her lip for a second, then stopped, almost spitting it out, if that was possible to do. Then she flew home. She didn't stop on the way or say hello to anypony else.

As it just so happened, Derpy had once had a conversation about this sort of thing. She remembered it distinctly, which was unusual for conversations, especially when they involved other ponies who she was since trying hard to forget about. In this case the conversation had been with somepony who meant a lot to her at the time, and still did, in a very different and strange way she didn't know how to put into words. The hard part to explain was why he wasn't around anymore. Why Derpy didn't see him, or call him, or say his name out loud, even to herself. Why she wouldn't even write it down.

She thought about calling him. His number had probably changed by now. She gave up pretty fast.

She watched T.V. for a little while. She liked the shows where ponies had to cook food very fast and very good, or the other three ponies who were sitting behind the table would yell at them and throw the food if it was extra messy or looked good on camera. Derpy liked the one where they threw the pies the best.

After a little bit of T.V., Derpy got bored. It felt hard to just sit down and watch something lately, or to just sit down and do anything, as a matter of fact. Every time she picked a task out of the bucket of paper slips in her head, she would set about doing it with her full focus, get maybe an hour involved, and feel all-at-once as though her entire body was drained to empty. A thousand boulders fell on her shoulders, and whatever she had set out to do at first with a lifelong interest, dedicated to checking just one precious item off the to-do list of her existence, became bland and vapid and devoid of any purpose or value. It became a big joke, that only she was in on, convincing herself for some silly reason that to learn and to change and to grow were all pointless pursuits.

She felt like a drop of water in the ocean.

During her conversation with the pony she no longer talked to, and that was hard, because there were a few ponies like that, so it helped if you knew which one she was talking about already... Derpy had thought really hard about what she'd do if she was stuck like this. Stuck in a world where nopony could see her or hear her, where she was more of a ghost than she already felt like.

He'd asked her if she'd hit somepony, eventually. If one day she'd get so frustrated, the rage would have nowhere else to go, and she'd feel something along the lines of 'Now let's see if you'll notice me, huh?'. Derpy had thought hard about that too. She'd never hit anypony before, at least not on purpose. She didn't know if she could imagine herself being that angry.

He'd told her to consider herself lucky.

Getting to sleep was hard, as usual. Derpy clutched her stuffy Mr. Snuffles and hugged him tight, but the problem with Mr. Snuffles is that he couldn't really talk back if you needed him to. He was a really good listener, but when Derpy was out of ideas, sometimes the very very quiet made her grumpy. Sometimes little noises made her grumpy, and sometimes loud ones did. Derpy wasn't very good with noise.

Tonight, the noise wasn't the problem. Derpy was wondering what her dreams would be about. She wondered if she'd vanished in the night like a puff of smoke, doomed to walk the clouds and never again hear the joy of her name in somepony else's voice. She thought about her mom. She did that a lot.

Eventually, she fell asleep.

The next day, Derpy decided to go out for breakfast. She lived near a few local restaurants and cafes, all of which had inviting specials and warm atmospheres, at least from what she was able to notice flying by them every day. She wondered if at the cafe somepony might notice her hat and tell her it looked nice, like had happened that one time. She wondered if somepony would sit down with her and ask her what her name was.

Every door she tried was locked.

The first one could have been coincidence, just somepony on opening shift who had slept in. She didn't see a sign no matter where she looked, which, even though it would have been more definite, would have also been a source of palpable relief. Door number two started the worrying going faster in her brain, and by the time she'd tested a full block and found neither a single place open nor a single pony inside, Derpy's chest was tightening again, and her breaths were getting shorter and shorter. She had to sit down on the side of a cloud for a few minutes to calm down and catch her breath before moving on.

One thought that stuck around was, if everything is closed, you won't be able to get any more food.

Derpy had about a box and a half of cereal and a half-jug of milk at home. She had maybe one pack of instant noodles and a moldy onion. Maybe some mustard.

She went straight to the grocery store next, and almost couldn't believe it when the doors opened automatically to let her in. But there was nopony else in the store, and when she got a few things and went to the cashier, there was a fancy machine for taking her money, and it even said 'Have a nice day!' as it dispensed her change. But that was it.

Derpy stocked up on milk, cereal, and cookies, then headed back home. She didn't bother calling into work to tell them she wasn't going to show up. She doubted she would have gotten an answer anyway.

After she'd had a bit to eat and no longer felt light-headed from hunger, Derpy made the flight down to Ponyville. Even at a distance from the market square, she could see ponies moving about from place to place as little coloured dots. The clouds were thick, but she kept on, and before she knew it, Ponyville market was in front of her, complete and full of ponies.

Derpy landed quietly in an empty stretch of grass next to a fruit stall. Her landings still needed some work, but she was crashing a lot less often lately. The pony running the fruit stall didn't seem to notice her, even as she walked through his booth and picked up a healthy-looking red apple. He didn't notice the apple moving, nor did he notice Derpy take a big, hungry bite out of it before she set it back down. Derpy left a few small coins beside the apple as she left, and it wasn't until she'd stepped a few feet away from the stall before the pony inside smiled and collected the bits. He also noticed the apple with a bite, shrugged, and picked the apple up to finish it off himself.

The part of the square thickest with ponies was the center, so Derpy headed there. She moved past ponies by themselves, ponies in pairs and on dates, and happy families of three, four, and more. Nopony seemed to notice her. They all just got out of the way, or didn't, keeping to themselves and speaking as though Derpy was as invisible as a breath of air.

"Hey," Derpy caught herself saying to a few ponies as they passed by her. She waved at them, even tapped a few on the shoulder as they walked by. "Hey, you. What's going on ? Can you see me?"

She grabbed somepony's shirt-sleeve and held on, but the pony tugged away until Derpy couldn't hold on, and she fell backwards, watching the pony straighten his sleeve as he walked away. The ground felt cold and wet. Derpy wondered if it had rained last night.

When she got up, she raised her right hoof up a little and stared at it. Her foreleg felt heavy, and seemed to shake slightly, like it wanted to move on its own. Derpy stared at it for a while, remembering her conversation with the pony she didn't want to remember.

After a big sigh, she flapped her wings, took off, and went home.

Another funny thing was that Derpy was pretty sure she'd seen a movie almost exactly like this too. The movie was a little different, but she did remember the main pony going through a period where he felt like nopony else could see him. She vaguely remembered the title being something about prairie dogs, but that was the best she could do. It didn't seem like very helpful information at the moment, anyway.

Derpy didn't want to beat around the bush: she could have done anything she wanted.

She felt overwhelmed by how little she wanted to do anything.

Stealing was out of the question. Murder, robbery... those were things you did if you were a bad bad pony who was sick inside. Derpy got sick sometimes, but she didn't want to have anything to do with hurting somepony, even if they couldn't see her and yell at her afterwards. She also didn't really want a lot of money, because she had mostly everything she needed, and whenever she managed to actually save for a few months and buy something else she wanted, it felt like a big prize and accomplishment, and maybe one day she could get another kitty to keep Mr. Snuffles company. And to pet, because you pet kitties, because kitties were cute.

She could have stolen a kitty, maybe. But that didn't feel right either.

A few times she went out to lie in the middle of the sky and see if somepony would notice her, or even bump into her on their way to wherever they were. But nopony did.

She could get some reading done. But she always had time to get some reading done, and she hadn't done any in a while, and it hurt her head if she read for too long anyway. Television would be the same as it always had been. Food would taste the same as it always did. Sleep was the only thing that felt different, and that was a fifty-fifty chance at best. Sometimes you got happy drifting off, sour waking up, and sometimes both were sour, and you felt like you'd cried a million times in the span of only a few hours. When you woke up, your eyes were dry, but your heart was chewed up in a blender and stored at a non-food-safe temperature for far too long.

Derpy wondered if she could sleep forever. She wondered if she stayed awake long enough, would all the things she could do start feeling like fun. She wondered if she could order a pizza, or maybe take one from somepony else who had ordered one and give them some bits as an apology.

After a while she got tired of thinking and went to sleep.

Derpy had two bowls of cereal the next morning. She filled them both up with a lot of milk, and made sure to eat up all the little crunchy and floaty bits before she drank the milk out of the bowl, tilting it up like a saucer with one hoof on either side. She made an 'ahh' noise both times, and licked off the bit of milk that was left-over on her upper-lip, and, once, her chin. Then she went to have her shower, and it was warm, and felt good, even if Derpy didn't.

Then Derpy went outside.

She stared up at the sky for a while, which was a little unusual, since she was in the sky, technically. There was a lot of sky that she never thought about, the clouds above the clouds above the clouds, and above those the sun, or space, she wasn't too sure... she'd never been up that high.

Derpy stared up for a little while before she left. She locked her door and made sure to put her key in her bag so she wouldn't lose it.

Then she went to check the stores again.

They were open, much to her surprise, but from the treatment of the ponies in line and the one cashier she managed to reach, nothing had changed beyond that. Words still fell on deaf ears. Derpy still waved to soundless expanses.

"Hey! Doesn't anypony notice me? I'm standing right here!"

That wasn't Derpy's voice. It came from behind her, for one.

Derpy spun around to find somepony else yelling and waving about in a group of other ponies. It was another pegasus, yellow coat and feathers, with green mane and a nifty yellow ribbon tied around it. She looked upset, which Derpy was good at noticing after she'd practiced a lot. It paid to know when somepony was upset, in Derpy's experience. Yelling was one good sign.

"Hey," Derpy said. Even though her voice felt weak from lack of use, the other pegasus seemed to notice her. She went through a tiny cycle of shock before she gasped and flew over. She started poking and prodding at Derpy, gently, but still often enough to make Derpy recoil a little bit from the constant barrage of pokes.

"You're real," the other pegasus said. She stopped poking Derpy and stood with her eyes wide. "You actually saw me. And heard me."

Derpy nodded.

"Yeah. I did."

"My name's Golden Glow. What's yours?"

"I'm Derpy."

Derpy and Golden Glow shook hooves. Then Golden Glow hugged Derpy, hard, and started crying, just a little.

Derpy hugged her back. She felt like she was saving her crying for when she got back home.

"Excuse me? Excuse me? Does anypony else notice what's going on here? I feel like I'm in a ghost-town! Hello?"

That was another voice, coming from the block of clouds near the intersection. Derpy and Golden Glow both noticed it, but Derpy was the first to fly, and Golden Glow followed behind her.

Somepony with a brown coat, black mane, and blue suit was waving his briefcase around and yelling at passing ponies. Derpy recognized the anger in his voice. She was glad the briefcase didn't look it had been used to hit anypony yet.

"Hey," Golden Glow said.

"Hey," Derpy echoed.

The pony with the brief-case stopped his wild swinging and turned to look at the two pegasi who had noticed him. He looked caught off-guard by their gentle interjection, as though he'd been reprimanded for cussing in class and was about to have his mother told.

"Oh," he said, beginning to blush slightly. "My word. You can both... you can see me?"

"The same thing was happening to me," Golden Glow said. "It started last night when I was at home. I called everypony I knew and not a single one of them answered. I couldn't believe it."

"This might be day three or four for me, and I'm afraid I'm starting to lose a bit of my cool," the suited pony said. "My name's Brick Layer, and, wouldn't you know it, I'm in construction contracting, which means I might not normally speak to somepony anyway for a few days if I'm working heavily on a project by myself... but this is just ridiculous. Don't you agree?"

"I do," Golden Glow said. Derpy just nodded. She seemed lost in thought.

Golden Glow and Brick Layer got on to talking very quickly. After a while they concluded to spread out and search the rest of the town for anypony else who was in a similar predicament. After some consideration, Derpy decided to go with them. But first, she wanted to go home and get a few things. Mr. Snuffles especially. It was important for him to come with her on adventures.

Derpy ate an orange and six cookies when she got home. She decided to buy the oranges on a whim, and so far, they were working out. She didn't like having to peel them, but she liked the way the peel looked when you took it all off, and she really liked the way the orange slices were squishy and juicy in her mouth.

As she passed through the living room, Derpy noticed her answering machine blinking. She still had an answering machine, and she liked it. She thought of it a little like a pet, or a friend, even though she knew it was just a silly machine there to help her record messages when she was away. Usually nopony left her a message. She wondered who it was from.

"Hey Derpy." It was her supervisor's voice. "It's been about four days since we've seen you in the office... just wanted to let you know we're all getting a little worried about you. You know if there's anything personal or private you're dealing with, you can come to us and we'll handle it with the utmost discretion. No details necessary. Just give us a call when you can? Be safe, hun." Click.

Before she'd gone out that morning, Derpy had left her hat hanging beside the door. It had gotten a little dirty over the past few days, mostly just dust, and she had to wipe it off a little bit with a towel to get it looking nice and clean again.

When she put it on, she felt like a pony wearing a hat.

It made her smile.