“Hi, Rarity!” Pinkie Pie called, her voice ringing out amid the hustle and bustle of Ponyville’s crowded marketplace. At the sound, the white mare turned, smiling tiredly at her rose-tinted friend as she bounced her way towards her.

"Wow, Rarity, you don't look too good." Pinkie said, giving her friend a concerned look. "You all right?"

"Oh, I'm fine." Rarity replied, waving a hoof. "I simply had to pull an all-nighter getting some orders out - my third this week. I simply haven't had time to catch up on my sleep yet is all. How are you?"

“Super!” Pinkie replied, smiling. “Well…”

Pinkie’s smile faded, to be replaced with a look of sadness so unusual for her that it made Rarity take a step back.

“Oh, my! Whatever happened?” Rarity said, concern filling her voice. She’d come to the marketplace to pick up some new materials, but if her friend needed her, she’d put everything on hold to deal with the problem.

“I-It’s no big deal. I’m fine, really.” Pinkie said, some of her customary happiness filling her voice. But Rarity knew better; she knew Pinkie Pie, and there was no way Pinkie was ‘fine, really’. Something was afoot.

“Pinkie Pie, it’s quite all right.” Rarity said. “You shouldn’t feel the need to hide your problems from your friends. I’m sure whatever it is, we can work through it together.”

“All right.” Pinkie said, looking around the marketplace. “B-But can we talk about it somewhere else? It’s kind of a… sensitive subject.”

“Of course!” Rarity cried, leading her friend through the streets of Ponyville and to Carousel Boutique, the unicorn’s home and business. Opening the front door and ushering Pinkie inside, Rarity’s mind flew through all the possible things that could’ve happened to her friend. She couldn’t even begin to imagine what kind of horrible catastrophe would have caused her friend to lose her signature smile.
Pinkie sat down on one of Rarity’s fainting couches, gave a sigh, and spoke, her eyes watering.

“S-Somepony hit me.” She said. “Really, really hard.”

Rarity stood there in stunned silence for several seconds, her mind attempting to process the information.

“Someone hit you?” she asked. “You?”

Pinkie Pie nodded, her eyes nearly filled with tears.

“I didn’t get to see who it was.” She said. “I was in a back alley on the west side of Ponyville Market - you know, the one with the three giant trash cans - when whoever it was klonked me on the back of the head.”

Rarity sat down on one of the fainting couches, her head spinning. Who could possibly have done such a thing?

“I did get to see what they hit me with, though.” Pinkie said. “It dropped to the ground when I did, and it rolled up against me. I guess whoever hit me left in a pretty big hurry.”

Pinkie reached into her mane and pulled her hoof back out of it holding something. She tossed it to Rarity, who gripped it tightly in her magic, turning it over and examining it. It was made of some sort of metal, and a large part of it seemed to be painted red and yellow, but it was so horribly mangled it was hard to tell exactly what it was.
The mystery was solved, however, when Rarity turned the thing over and the words ‘Caffeine Free’ stared back at her.

“This is a soda can.” Rarity said.

“Yeah.” Pinkie replied. “I dunno what happened to it; it felt full when it hit me.”

The can, if it was at all possible, was crushed even more as Rarity’s magic compressed the can of soda into a smaller, more mangled hunk of metal.

“How dare they!?” Rarity said, her voice quiet and cold.

Someone had hit her friend; had hurt her, in an act of deliberate, premeditated violence. She would not, could not let such an act go unpunished!

"Don't worry, Pinkie." Rarity said, rising from her couch and heading toward the door of the Boutique. "I am going to find whoever did this and bring them to justice."

"Yeah, but-" Pinkie Pie began, only to be cut off by the door of the boutique swinging open and then slamming shut.

The sound of Rarity's hooves echoed through the crystalline hallways of Ponyville Castle, the sound reflecting off of the walls and hitting her ears, if anything louder than before.
Shortly after leaving her home, Rarity's anger had cooled, and she'd been able to think about the matter. She'd come to a simple conclusion early on; she had no idea where to start looking for this mysterious soda can thrower.
So, after a few minutes' thought, she'd decided to ask Twilight for help.
Soon, she came to the door of the library and opened it. Twilight was inside as she always was nowadays, reading three books and sipping some tea.

"Something urgent has happened!" Rarity cried, flinging a hoof out and using her best 'catastrophe' voice. "Something positively dreadful!"

Twilight looked calmly up from her books.

"Afternoon, Rarity." she said, smiling. "Is everything okay?"

"No!" The unicorn cried, placing a hoof daintily atop her head. "Someone has assaulted Pinkie Pie!"

At this, Twilight's eyes narrowed, and she returned to her books, looking over them at her friend with an odd expression.

"Someone has, huh?" she said.

"Yes! It's simply the worst! Possible! Thing!"

"...And what, exactly, did this 'mysterious attacker' hit Pinkie with?"

At this, Rarity stopped the theatrics and looked at Twilight, a thoughtful expression on her face.

"It's the strangest thing, actually." Rarity said. "Somepony hit her with a can of soda."

"Funny, that." Twilight said, devoting her full attention to her books again. "Maybe one of our other friends knows who did it."

"And you don't?"

"Not in the slightest." Twilight replied, lowering her books and sighing. "All I know is this; The pony who attacked Pinkie is so shrouded in mystery, it's almost like they don't even exist. Spooky, huh?"

"Well, then I am off!" Rarity cried. "To visit Rainbow Dash!"

"Good luck with that." Twilight muttered as Rarity turned and dashed away.

"Rainbow Dash!" Rarity called, gazing intently at the front door of her friend's cloud home. "Are you in there?"

"Rarity?" Rainbow Dash called from inside. "Is that you?"

"It is!"

The door opened to reveal Rainbow Dash's face, a worried look on her face.

"What's up?"

"Somepony has attacked Pinkie Pie!"

Rainbow's face fell into a frown, and she gave Rarity a look.

"Go away, Rares." she said. "Not in the mood."

"But Rainbow-"

"No. I'm not even gonna let you talk about something like that. Not so soon after what happened. Beat it, before I get really ticked and throw something at you."

The door slammed shut.

Rarity gawked. Was this mysterious assailant so deadly, so intimidating, that even Rainbow Dash feared to speak of it?
There were only two avenues left to her: Whatever this pony was, it couldn't have gotten to Applejack. If it had, she'd just have to interrogate Fluttershy; the mare was extraordinarily brave when she needed to be; she was sure she could impress upon her the importance of her mission.

"What's goin' on, Rares? It ain't like ya ta run all this way." Applejack asked, once Rarity had caught her breath; she'd ran all the way from Rainbow's house to Sweet Apple Acres, leaving her mane looking as if she'd been dragged halfway to Canterlot on her head.

"Ain't like her ta run anywhere, let alone with her mane lookin' like that." Applejack muttered to herself as Rarity gave herself a quick once-over.

"Pinkie Pie has been attacked!" Rarity cried. "And - what's worse - her attacker seems to have scared everypony into silence; they won't hear a word of Pinkie's problem!"

Applejack sat for a few minutes, her face a mask. At last, she spoke thusly:

"I don't really know who or what this pony is, but Ah know... Now, who'd Ya'll talk to again?"

"Rainbow, Twilight, and Pinkie."

"Right, them. Fluttershy definitely knows, then." Applejack said, her eyes shifting nervously back and forth, refusing to meet Rarity's. The designer didn't notice, though, so great was her shock. So this mysterious soda can wielding pony had that much influence.

"Applejack, please." Rarity said quietly, her voice pleading. "Whatever this pony has said or done to you to ensure your silence, I am sure we can handle the threat. It's all right; you're the Element of Honesty. You can tell the truth."

"No, A-Ah seriously dunno." Applejack said, beads of sweat beginning to form on her face. "But Ah know Fluttershy knows. Please just go ask her. Like, right now."

Rarity pulled her friend into a tight hug.

"Don't worry." she said. "After I find out who did this, I will return to help you. This, I swear."

"T-That's mighty kind of ya." Applejack said, sweating bullets now. "But Ah really don't think-"

"I must!" Rarity cried. "What sort of friend would I be!? I must go glean what I can from Fluttershy, but rest assured; when I return, we will talk at length about what to do about this vile excuse for a pony."

The door opened, then closed. Applejack slumped in her chair, the picture of relief.

"I dunno what happened to it; it felt full when it hit me."

Fluttershy's door burst open and Rarity walked in, eyes as ablaze with righteous fury as two frazzled, bloodshot orbs could be. They fell upon Pinkie and Fluttershy as they sat in the latter mare's parlor, both of them wearing stunned expressions.

"You've told her what happened?" Rarity asked. Pinkie nodded slowly.

"Good." Rarity continued. "Fluttershy, we need to work quickly if we are to catch this unnamed threat. I have an ample supply of rope, string, and other materials we can use for traps. You have-"

"Traps?" Fluttershy squeaked, shrinking into the couch.

"Indeed! Your animal communication skills will give us the eyes and ears we need to locate this ruffian. Quick! The game is afoot! You come too, Pinkie; our first stop will be the scene of the crime!"

Without another word, Rarity turned and left, leaving a stunned pain of ponies in her wake.

Rarity, mane unkempt, eyes bloodshot, and left ear twitching, arrived at the 'crime scene' out of breath, but determined to carry on. She retrieved a length of ribbon - she always had some on her person for emergencies - and cordoned off the area, giving steely glares to all passers-by; any one of them could have been Pinkie's assailant.

Pinkie Pie arrived later, the other Elements in tow. Rainbow Dash's face was unreadable, Twilight's a mix of boredom and exasperation, Fluttershy's was plastered with worry, and Pinkie and Applejack both looked rather guilty.

"Have you any leads?" Rarity asked, when they arrived.

There was a brief silence. Twilight coughed.

"Ya see," Applejack began. "About the whole 'attackin' Pinkie with a can a soda' thing..."

"Wait!" Rarity cried, her eyes narrowing. "I never told you it was a can of soda."

There was another silence. One could practically hear the gears in Rarity's head turning.

"Applejack..." Rarity said, her voice in that threatening tone that somehow manages to be as forceful as a shout despite being just above a whisper in volume. "how could you?"

Applejack backed away slowly, hoof out in front of her in a placating gesture.

"Now look, Rares." she said. "L-Let's not do anythin' we'll end up regrettin' here."

"Rarity..." Pinkie said, her eyes cast downward.

The white unicorn advanced slowly, eyes boring holes into Applejack's.

"Pinkie is our friend!" Rarity said. "She trusted you! I trusted you! And all this time, you were playing the victim, when really, you were the vile, cowardly, abhorrent scum who did this! The Element of Honesty, betraying her closest friends!"

"Rarity."

Rarity's nose was pressed up against Applejack's now, the latter mare looking anywhere but at her friend; a very difficult task when the friend in question took of almost all of her vision.

"Are we even friends to you, Applejack!?" Rarity shouted. "Or has everything been a lie? Everything we've known about you, everything you've said to us, were those lies too!? Is Applejack even your real name!?"

"Okay, I'm ending this here." Twilight said, sighing. Her horn lit up, and Rarity was lifted from her friend, foam beginning to form at the corners of her mouth.

"So you're in on it too, Twilight!?" she cried. "How many of our friends aren't horrible ponies!?"

"Rarity, STOP!"

Pinkie Pie was in her face then, hair deflating fast and a near-manic look in her eye.

"Pinkie-"

"Just stop!" Pinkie yelled. "It was a joke, okay!? A joke! You were supposed to be all shocked, and then I was going to say 'luckily for me, it was a soft drink', and we both would've laughed, because all sodas are soft drinks, and then I would've gone out and bought us a couple of cans of root beer! It was a joke, alright!?"

There was silence again. Pinkie Pie was breathing heavily, her eyes filling up with tears.

"But then you ran out, and I couldn't find you, and so I decided to at least get Fluttershy with it, and then you came in, and I had to go round up the others, and now you and Applejack hate each other and it's all my fault!"

Pinkie began crying, and something unexpected happened.

Rainbow Dash burst into peals of laughter, falling over, so great was her mirth.

"Oh, man!" she cried, amidst chortles. "You should see the looks on your faces!"

Getting to her hooves, Rainbow walked over to Pinkie and put a hoof on her shoulder.

"Man, Pinkie, you're like an angel of justice.." Rainbow said. "That was beautiful! A work of art! A prank like that belongs in the Hoovre!"

"Rainbow Dash, this is no time to be laughing." Fluttershy said sternly. The mirth faded from her friend's eyes.

"As opposed to a few days ago?" she replied. "When you used the Stare on me? Yeah, that was the perfect time to laugh."

"Rainbow-" Twilight began.

"Don't you 'Rainbow' me, Twilight." Rainbow Dash growled, fixing her friend with a glare that could crack stone. "You don't get to talk to me like that after the way you messed with me, let alone say I can't laugh at this; you guys all laughed your heads off when you made me apologize for something I didn't even do and wasn't even wrong, but Rarity gets carried away and yells at Applejack? Serious as a freaking funeral."

Rainbow turned, unfurling her wings.

"Rarity, Pinkie, consider yourselves off of my list. You're cool, just like Fluttershy. Twi, AJ, you'd better watch out; after I'm done with you, you'll realize Pinkie and Rares got off easy."

And with that, Rainbow Dash flew away.
There was a long silence.

"Well, at least now you know why none of us would help you." Twilight said, releasing Rarity from her magical grip. "Pinkie had already pranked us, and we weren't about to ruin the joke."

Twilight slowly walked away, muttering something about setting up wards, leaving Pinkie, Applejack, and a panting Rarity behind.

"Look, Rares, Ah'm really sorry." Applejack said. "But Pinkie made me Pinkie Promise not ta spoil things fer ya. Ah hope ya can forgive me."

And with that Applejack left, shaking her head.

Pinkie Pie sighed.

"I'm sorry for letting things get out of control." she said softly, nuzzling her friend. "If you're still up for it, do you wanna have that root beer now?"

"I would enjoy that, yes." Rarity said.

And then she passed out.