The Annual Ponyville Heart's Warming Day Festival was in full swing, with decorations spewed all across Ponyville. Many ponies were selling Heart's Warming gifts and assorted, with Pinkie Pie of course selling cupcakes. There was a chill in the air; winter was right around the corner, which would blanket all of Equestria in snow within a few weeks.

Derpy walked through the center of town, delivering a letter to Twilight, who was in her house, working on a potion. As she was walking through the celebration, she grabbed out a muffin, and started munching on it. Derpy always loved Heart's Warming Day, it was her favorite holiday.

Derpy then came to Twilight's tree house, and walked through the door. Twilight was hard at work on a potion, and Spike was on the floor, asking Twilight if he could go out to the Festival.

"Please Twilight," he pleaded, "I'm not much help here!"

Twilight looked up from her potion, and said, "Alright, Spike, just don't overload on Pinkie's cupcakes, you know what happens next." Spike groaned, and walked out the door. Twilight saw Derpy walk in, and said hello and wished her a happy Heart's Warming Day.

"Thanks Twilight," Derpy said, "I've got a letter, from a…." She struggled to read the return address, gave up, and gave it to Twilight. She opened it, and squealed. It was from Princess Celestia, giving a form to receive a free encyclopedia series.

"Thanks for bringing this, Derpy," she said, with a smile on her face her eyes gleaming, "Did you get any gifts for Heart's Warming Day?"

"Uh," Derpy said, "Yeah, I got a new sack, and a dozen muffins! How many is that, Twilight, I'm not good at that counting thing."

"That's twelve, Derpy," Twilight said, sweeping her pink and purple mane out of her eyes, "Well, here, Derpy, happy Heart's Warming Day." Derpy smiled as Twilight handed her a box of blueberry muffins.

Derpy then said, "Thanks, Twilight! Happy Heart's Warming Day to you too! I've got to go now, got something for Rarity." She then walked out, but on the way out, her wing hit a small vial of a chemical, and dropped it into the pot Twilight was making her potion. Twilight didn't notice, and went back to work.

As Derpy walked out, she then went over to Rarity's house, on the other side of town. After she gave Rarity her letter, she walked back into the square, her work done. Twilight had then set up a stand, selling cups of her potion, which helped you feel happier, to keep the celebrations going.

It was when Miss Cheerilee drank the potion, she immediately went to the ground, and began to vomit and shake uncontrollably. Everyone went to see what was wrong, and Doctor Whooves went to her side to try and help. It was then that Cheerilee snarled, and bit Whooves in the neck. He screamed, blood running down his neck, and crawled back. Cheerilee went back up, and attacked the crowd.

Everyone was panicking, and Pinkie Pie wasn't helping, running around, telling everypony to run for their lives. She screamed as Cheerilee tackled her, and was about to bite her, when Rainbow Dash came out of nowhere and pummeled Cheerilee.

By now, a bunch of ponies were infected, and were attacking those who weren't. Fluttershy, being scared to death, ran as fast as she could, with Doctor Whooves right behind her, snarling, blood drooling out of his mouth. Twilight used her magic to suspend Whoof in the air, and threw him to the ground.

"Run Fluttershy!" She said as she kept Whooves on the ground. Fluttershy, the others and Derpy ran into her tree house. Twilight grabbed Spike, and locked the door behind her.

"Alright, does anypony know what's going on?" she asked, panting in between every other word.

"I don't know, Twilight," Applejack said, "But it seems that everything has gone to tarnation. I hope Applebloom is alright."

"Oh my gosh," Pinkie Pie said, running all around the tree house, "What is going on? Are they zombies, are they even alive? What do we do? I'm so panicking right now!"

"Well," Rainbow Dash said, "It was Twilight's potion that made Cheerilee go insane. What in the name of Celestia did you put in that?"

"I don't know, Rainbow Dash," she said, opening her potion book, "The book says add a pinch of salt, vanilla and cocoa, then add a tablespoon of water and sugar, and mix it with pink food coloring. Then, you add the happiness solution, three teaspoons of daffodil nectar per cup. I was doing that, but when Derpy came in and delivered this letter, either she or I must have put in something by mistake!"

Everyone then began to inspect the shelves, and Twilight then said, "Hey, where's my vial of Red Reviving Juice, I put it right here!"

"Well, Twilight, darling," Rarity said, "What does it do?"

"It's supposed to bring someone out of death's grip if they died within the last hour, but if given to a live pony," she said, freezing immediately, "Derpy, did you put that vial in the potion mix?"

"Uh, I think so," Derpy said, tilting her head, "Was it in a small cup thingy right here?"

"Yes, Derpy, yes!" Twilight said, "Oh no, if you give that to a live pony, it turns them insane, and they begin to attack the living! No, this can't be happening, it's Heart's Warming Day, this is supposed to be a happy day!"

"Uh, Twilight," Rainbow Dash said nervously, "Not to freak you out at all, but they're breaking through the door!" She screamed as Cheerilee, Doctor Whooves and Cranky broke through the door, moaning. Rainbow Dash flew back, and screamed for somepony to do something. Twilight used her magic to smack the potions book at their heads. Cranky's head exploded in blood, and splattered Cheerilee and Doctor Whoof.

"Smash their heads!" Pinkie Pie screamed, "It works! Smash them all!" She grabbed a heavy book, and busted Cheerilee's head open. Rainbow Dash then grabbed Derpy's sack and pummeled Doctor Whooves' head into a bloody pulp.

"Die, die, and die again!" She said, tears streaming down her face. "Die, die, and die!" After Doctor Whooves was dead, she then began to cry. Fluttershy went up to her to console but she snarled at her, saying, "Get back! I'm a monster, a monster I tell you!"

Applejack then went up to her, and smacked her in the face, saying, "What in tarnation are you doing, Rainbow Dash? You need to get yourself together! Now, we need to get some weapons to protect ourselves with, and go tell Princess Celestia what's going on. Spike, you need to write in advance to tell her we're coming, and something seriously wrong has gone wrong in Ponyville." Spike nodded, and the rest scoured the house, looking for something to protect them with.

"Alright," Applejack said as she found a fire ax.

"This will suffice," Rarity declared as she picked up a large knife.

"Sweet," Rainbow Dash smiled as she picked up a baseball bat.

"Um, alright," Fluttershy said as she found a first aid kit. "I'm not one for fighting, sorry everypony."

"Yes, yes, yes!" Pinkie Pie screeched as she somehow found a sword in the house.

"Will this work?" Derpy asked confusedly as she found a muffin. Rainbow Dash said no, and handed her a staff. Derpy shrugged, ate the muffin, and picked up the staff.

"Let's go, everypony." Twilight said, wielding a magic staff. They opened the door, and gasped at the chaos in Ponyville.

Most of the town was on fire, and the Town Hall was collapsed. More of the Pony Zombies walked through the town, moaning and looking for their next meal. Fluttershy looked, and pointed to the train station, where live Ponies were boarding the train to Canterlot.

They all broke into a run, and made a beeline for the train station, smashing Zombie Pony's heads along the way, all except for Fluttershy, who chose instead to close her eyes and run for the train station. That was how she was tackled by Lyra; and was about to be eaten, when Twilight zapped Lyra with her magic staff, and told Fluttershy to get up. She did, and ran for the train depot.

As they got onto the train, Applejack saw Apple Bloom, Scootaloo, Sweetie Belle, Granny Smith and Big Macintosh. She turned to see what they were looking at, and saw Sweet Apple Acres in flames and more Pony Zombies walking through the flames, completely unharmed by the fire. The train eased forward, and then they were off.

The train was alive with talking, shouting and crying as everypony had something to say about what happened, like, "Is Doctor Whooves alright? I heard he got bit." Or "This can't be happening" and "Has anyone seen my filly, she was by my side when she got on the train!"

The group of Twilight, Fluttershy, Rainbow Dash, Derpy, Applejack, Rarity and Pinkie Pie sat in their seats, stony-faced. Applejack lightened up as the CMC, Granny Smith and Big Mac came over to share their relief that their sister and granddaughter was alright.

"Is everypony alright? No one got bit?" Applejack said, hugging Applebloom tightly.

"Nooooooope," Big Mac said. Applejack hugged him too, and started crying.

"Oh, cheer up, Applejack," Granny Smith said, "That virus can't spread faster than this train. That is, unless those Zombie Pegasi can fly. Never mind that, honey, we're all fine." She began to smile, but then saw Sweet Apple Acres again.

The train kept moving on, and they saw the level of destruction die down, but everypony could still see the smoke from the fires in Ponyville. As they stopped in Fillydelphia to refuel, everypony climbed out to get something to eat or to something to protect themselves with.

The small group came up to an arms store, and walked in. The shopkeeper, a large Pegasus stallion with a broad black moustache, gray coat and red mane, with a revolver cutie mark, welcomed them.

"You need something heavy, or just a peashooter?" He asked, extending his hand, "Big Arms Joe, owner of Big Arms Guns and Ammo, whattya need?"

"Something to kill a pony," Rainbow Dash said, scanning the shelves, "You got something like that?"

"I ain't selling no gun to anypony conspiring to commit murder." Joe said, "I hope you know that."

"I know," Twilight said, "But there was a viral virus back in Ponyville, and it turns them into flesh-eating zombie things. We need something to protect ourselves with."

"Well," Joe said, "With that, 15% discount for all of you! Pick something you like, I got everything you seek. I got a Beretta M9 for the shy little mare," he said gregariously and motioning to Fluttershy, "And for you, my lady, a Kalashnikov AK-47." He gave the AK to Derpy, who thanked him and smiled.

As they scanned the store, everypony decided on a weapon. Rainbow Dash picked a G36C, Rarity an MP7, Twilight a Barrett .50cal, Pinkie Pie a M249 LMG, and Applejack a Benelli M4. After much persistence, Fluttershy finally took a M1911 pistol for protection. They paid, thanked him, and walked out.

By then, word though Fillydelphia had spread of the Ponyville Virus, as it was now being called. Guns and ammo were being bought by the thousands, and people were panicking. Twilight thought they should get going to Canterlot, and they all agreed, except for Derpy, who said she wanted a muffin.

They climbed back onto the train, ammo strewn all across their bodies. The engineer at first said for them to drop the guns, but after Rainbow Dash threatened him, they pulled out of the station. They were on their way to Canterlot, to tell Princess Celestia of the growing problem.

Rainbow Dash turned on the TV to watch some cartoons, but was disappointed as emergency broadcasts regarding the Ponyville Virus had reached its way onto the airwaves, and all normal programming was suspended.

"Great," Rainbow Dash said, "There was supposed to be a Daring Do marathon. Now all I think about now is them!" She threw the remote, and began to pout.

"Come on now, Rainbow Dash," Fluttershy said, "It could be worse, one of us could be them. That would make it only that much harder too…"

"Not now Fluttershy," Rainbow Dash said, "I'm not in the mood."

"Oh, okay," Fluttershy said, "If that's what you want."

The train went on, and the group of friends was silent until Canterlot came into view. Twilight perked up, saying she hadn't been to Canterlot in a while.

"I only wish it was under better circumstances." She said glumly as the train pulled up into the station. They all broke into a run towards the Royal Palace. The guards said hello to them, but then quieted themselves as they saw how seriously armed they were.

They stormed into the Royal Court, and Princess Celestia looked up, and said, "Ah, yes, I have been waiting for you to show up. Now, what is this problem you have?"

"Problem?" Rainbow Dash said, "Oh, there isn't a problem, just ponies eating each other!"

"Oh, that seems to be," Celestia said, "Very troublesome, more than those parasprites in Fillydelphia. Yes, I shall dispatch some military units there immediately."

"Princess Celestia," Twilight said, "You shouldn't send them to just Ponyville, you see, it's spreading throughout Equestria, we think the first of them should show up in Fillydelphia by tonight, and it's already five o' clock! This virus could spread from Las Pegasus to Baltimare in no time at all! We should send them throughout all major cities and towns."

"Alright," Celestia said, "Any, unusual characteristics of these, ponies?"

"Well," Twilight said, "I noticed their coats and manes have faded colors, and they have blood running down infected wounds anywhere on their body. I think their cutie mark also has faded some as well."

"Keep going," Celestia said nodding towards a unicorn, which immediately began writing down the characteristics.

"They also have sagging eyes, and they moan, a lot." Twilight finished, and Celestia nodded towards her.

"That information will suffice Twilight," she said, "I will dispatch the appropriate military forces to major points of infection and possible infection sites. You can go now, Twilight." Twilight and the others soon walked out of the court, followed by Derpy, who didn't know what just happened, but smiled at Celestia, and walked away.

"Princess Celestia is nice," she said, smiling, "I like her."

"Maybe that's why she's a princess, Derpy!" Rainbow Dash snarled. At that, Derpy began to cry, and ran off.

"Rainbow Dash," Rarity scolded, "That was not nice at all. You know Derpy; she can get into all sorts of trouble. Derpy, come here, Derpy, she didn't mean it!" She then ran after Derpy, and the others followed.

Derpy seemed to be running anywhere and everywhere. Crying like a baby, she ran out of the castle, and into the rodeo, which was empty in the evening sky. The others caught up with her, and they began to console her.

"I'm sorry, Derpy," Rainbow Dash said, "It's just been the worst Heart's Warming Day, ever." The others agreed, and gave Derpy a muffin. She sniffled, smiled, and ate the muffin. She tore off a piece, and gave it to Rainbow Dash, who smiled and ate it.

They then got up, and walked out. The sun had set over Canterlot, and they were getting tired. They decided to go find a room at a hotel, but then a message from Princess Celestia told them they had a room in a tower at the castle.

They went back to the castle, and were escorted to their room. The room was elaborate, and Rarity would've squealed if she hadn't been so tired or there weren't the given circumstances. They all had their own beds, and a bathroom. They took off their ammo strips and magazines, and climbed into the soft beds. They immediately began to fall asleep, and forgot all about the horrid day they had.

I hope you like it so far! This was the first idea I got for a fanfic, and I finished it a few months back. I'll be posting the entire story up by today. So, Red Reviving Juice, I really couldn't come up with a better name. Basically it's like a defibrillator potion, but if used on the living, the results are catastrophic. I also decided to use modern-day weaponry; I thought it would make it easier instead of making whole new guns. So, leave a review and maybe a favorite!