Still panting a little bit for the excruciating run she had gone through, Rainbow looked at every corner of the room. That place was very unfamiliar to her. Among the structures that composes the complex, that one was the only that she never visited during her first days as a Wonderbolt. The room was a empty, dark big hall that was almost long as half of the paved runway used for the training. The feeble light passed through the windows being almost close to the ceiling. Her attention was caught by the big red curtain covering half of the room.

"Since by then they need a curtain?" Rainbow asked perplexed.

"Is the exact same question that I have in this moment," Meadow said before noticing Moon Shard being near to Rainbow. "You are the one who saved Rainbow."

"Spare you flattery for somepony else." Moon said almost coldly.

Rainbow looked at him with narrowed eyes, a little annoyed by the unicorn's apparently arrogant tone. Meadow, on other hooves, couldn't help but feel a little disturbed by the the red runic symbol fully covering his right eye.

"Ehm... Sir?," Meadow called. "What happened to your eye?"

"That should be the last of your problems." Moon replied impassive.

Perplexed by his statement, Meadow looked at Rainbow, who was visibly shaken for the whole chaos happening in Cloudsdale. Seeing the city being crumbled reminded her of the fall of Ponyville. What she saw was real, and yet she wanted to think that it isn't.

"Rainbow, I'm sorry for what you had gone through." Meadow said apologetic. "Allow me to explain."

"You better do it, because I don't even know if you had lied to me," Rainbow pointed out while glaring at her. "How that happened!? You said that Cloudsdale was protected by the barrier!"

"It wasn't my intention to hide anything from from you," Meadow replied. "Let me explain. Spitfire was about to perform some experiment before she could plan to use the vaccine to cure the infected ponies."

"What experiment?" Moon asked.

"Spitfire, Fleetfoot and the others were indeed vaccinated," Meadow explained. "However, nopony used the vaccine to infected ones. So, to not make any miscalculation, Spitfire and her group captured a infected one and tried to test the vaccine on it... Unfortunately, it managed to escape and spread the infection. That happened twelve minutes after I left your room."

Rainbow looked at her in disbelieve. That can't be real for her. Her eyes being filled with incredulity, with her face slowly assuming a angered one.

"You cannot be serious," Rainbow said angrily. "And you had brought that thing inside of it, fully knowing the risks!?"

"Strange that the Wonderbolts were unprepared for that risk," Moon pointed out, looking unconvinced.

"Not at all. Before all of this, Spitfire promptly gathered the most of the medics in town not only to keep them safe, but also to assist the injured healthy ponies that they managed to find." Meadow informed.

"And the other patients? And me?" Rainbow retorted. "I could had died if wasn't for the old man, you know!"

"Look, you where brought in the hospital right before being informed about the experiment!" Meadow muttered stressed out by Rainbow's inquisitive questions. "Nopony, not even I, could possibly know that would happen!" Her irises shrunk. "What else do you want me TO SAY!?" She paused, panting for a moment and the calming down upon seeing Rainbow's freaked out expression. "I'm sorry... If... If only we could know that would happen."

Rainbow's anger slowly dissipated, replaced only by empathy toward Meadow, who felt guilty about that. "Meadow. I am-"

"Save that for later, both of you," Moon interrupted them. "I think we aren't alone in this room."

"There is somepony else?" Rainbow asked.

"Probably," Moon looked at Meadow. "Say... What about the rescued ponies, the refu?"

"They... They were put inside special facilities under Spitfire's orders," Meadow responded hesitantly. "They are actually under medic observation."

"Meadow?" Rainbow looked at Meadow with a worried look. "Were did she had brought them?"

Before Rainbow could get any answer from her, they were interrupted by a familiar, female voice coming from behind the curtain said.

"You are just in time," She said. "Sorry for keeping you in the dark but you know, I got a little busier... Recently."

A yellow pegasus, being Spitfire came out of the curtain with an unusual calm and wearing a full Wonderbolt uniform with googles included, much to the two mare's surprise. The instructor was then joined by Fleetfoot, also wearing a uniform at all, and by Meadow who flew away from the two and landed nearby the curtain, standing next to her.

Rainbow instantly noticed something wrong with Spitfire, even with the lack of light that darkened the room. The color of her mane, wings, mouths and tails looked more pale than usual. What's more was her strange reaction upon seeing Moon Shard.

"Surprised to see me?" Moon asked, almost grinning.

"N... Not at all." Spitfire stammered.

"Wait a second!" Rainbow looked at Moon and then back to Spitfire surprised. "You know him?"

"O-of course," Spitfire cleared her throat. "He's one of the contributors in the development of the vaccine, back in Canterlot."

"Meadow told me that you brought a infected pony to test the vaccine. Is that true?" Rainbow asked, hesitantly.

"You are right." Spitfire admitted. "That was the reason why we have brought that thing here."

"You see," Fleetfoot said. "We weren't sure if the vaccine works on the infected too. Spitfire planned to use that on the infected ponies who were still intact. However... He was on the loose."

"Wait, the barrier was supposed to keep the undead at bay. How did you even do that?" Rainbow demanded.

"You couldn't know that," Spitfire remarked. "You see, while the barrier covered the entire Clodsdale, there's only one gate that acted as a filter. And is really guarded."

"We have not time for chit chatting," Fleetfoot reminded.

"Indeed," Spitfire agreed. "We have plan to stop the current infestation."

Rainbow wanted to believe her words, and yet something is telling her that to keep pressing. And that is what she does.

"Spitfire, what do you mean with us being just in time?" Rainbow questioned bluntly.

"Rainbow... You have all the right to ask that to us," Spitfire said calmly. "That is-"

Spitfire's attempt to justify her words was disrupted by Moon Shard snickering and then slightly laughing. Rainbow looked at him with as if she was for his sanity.

"Old man?" Rainbow called him worried.

"So, at least you had admitted that you had committed a mistake," Moon said gleefully before returning into his own stern tone. "Please, that wasn't entirely the truth."

Rainbow looked at him dumbfounded. "What?"

"Moon Shard. What are you talking about?" Spitfire asked.

"You said that you brought a infected one," Moon said, this time grinning for real. "That is technically half true,"

"Explain yourself." Spitfire ordered.

"There are three types of zombies in this mess," Moon informed. "The Lessers, being the normal one, and the Flailers. In our case, the infected one that you had brought there... Is a zombie of the third type."

"Old man, you don't make sense!" Rainbow tried to stop him.

"Let him continue, Rainbow Dash." Spitfire commanded.

"What is the meaning of this?" Fleetfoot demanded irritated.

"I had contributed to create the vaccine after all, so I can recognize a infected of that type when I see one," Moon indicated Spitfire with his hoof, glaring at her. "I'm looking right at you, lady."

A sepulchral silence grew in the room. Nopony in the room reacted at his words and accusations. Rainbow Dash, however, looked at him incredulous. She couldn't believe was she heard from him.

"Stop this nonsense!" Rainbow shouted. "They were vaccinated! There's now way they would be infected!"

"Oh, really," Moon asked nonchalantly. "Then tell me. Did you had saw the real effects that the vaccine has on the infected?"

"I... I.." Rainbow stuttered, not knowing what to say.

"What was the vaccine for you?"

"What kind of stupid question is that!?"

"A fiasco." Spitfire said bluntly.

Rainbow darted her eyes toward Spitfire with a baffled expression. The sergeant's words harshly contradicted what Meadow said about the antidote to the plague to her. Rainbow wanted to believe she didn't heard that. But then, Spitfire, of all ponies, snickered nervously, which completely baffled her. She never saw Spitfire acting like this. More disturbing was the fact that Meadow and Fleetfloot didn't gave any reaction at all.

"Spitfire... Are you joking around?" Rainbow said, disturbed by her reaction.

"Rainbow Dash..." Spitfire chuckled a little bit. "Do you think... I am... Joking around?"

"So you know what it is?" Moon asked.

"You heard how I called this cure of yours..." Spitfire barely recovered her composure, only to slam her hoof on the floor while screaming "A FIASCO!!"

Spitfire's last words echoed through the hall and inside Rainbow's head. Her hope that this nightmare could be ended quickly was instantly crushed in front of her eyes. However, only one question remained.

"How?" Rainbow asked.

"Let's put a end to this farce, shall we?" Spitfire proclaimed.

Suddenly, claws popped up from both Spitfire's hooves, piercing through her flesh. She then took her goggles and tossed them away while keeping her eyes shut. Then she proceeded to tear her uniform apart, revealing her own real appearance. Once she finished, she slowly opened her eyes.

With that, Rainbow got a full view of Spitfire, in the most horrible way that she never expected to see. She saw the pallor of the sergeant's wings and mane being strange but she didn't had considered that being a signal. The color of Spitfire's coat, mane, tail and feathers were faded, parts of her figure were torn apart, exposing a few bones, a few muscles and part of her rib cage. Bloodstains smeared her chest and neck, and her hooves. Spitfire looked at both Rainbow and Moon with seemingly white, lifeless eyes. Eyes devoid of vitality that were in contradiction with her face of lucid madness.

The same thing happened with Fleetfoot, who had her hooves sprouting claws, being metallic ones. Having saw Spitfire revealing herself, she followed suit. Once she's done tearing her uniform apart, her body revealed to be almost the same as Spitfire. Same faded colors, same parts being torn apart and same insane visage. The only exception was her left eye being fully red and her neck's bones being exposed.

Rainbow took a few steps back. Her eyes being wide opened and her body trembled for the fright. The situation was bad enough, but she didn't expected to take this twisted turn. Her instinct was telling her to step away from the creatures who who used to be her friends, yet she doesn't want to listen that.

"Tell me that is not real." Rainbow said in denial. "This can't be happening!"

"But IT happened, Rainbow," Spitfire countered with a almost coarse tone. "Not even I saw that coming... Heheheheh... Now my own soul is all but ruin."

"You were vaccinated against the plague!" Rainbow shouted.

"Are you dense or what?" Fleetfoot asked crudely.

"Celestia LIED to us!" Spitfire shouted. "Or, I should say, she never, ever predicted the side effects that the vaccines would have on us! Her research ponies never made a test on their own... So they used us as specimens... Is unacceptable."

The scene was both macabre and surreal to be fully believed. Rainbow doesn't even what to think anymore. Her friends were now similar to zombies, and yet they managed to retain her emotions and intelligence. And now they were blaming Celestia for their conditions. Rainbow turned toward Moon with a angered look.

"If you know something, you better tell me what happened to them." Rainbow said menacingly. "You are the one who helped in the creation of the vaccine, right?"

"That, my friend," Moon said sardonically, indicating the undead Spitfire. "Is the third type."

"Again with this third type. What do you mean with that!?"

"The lethal one, also know as Undementia."

"Undem... What?" Rainbow asked in confusion.

"They are a rare type born by a medic's attempt to create the vaccine," Moon said. "That one being White Chime. He tested the vaccine on both the livings and the infected ones. It worked like a charm at first, but can't do nothing against the plague that is the Necromyth. Just like he plague created the Flailers by twisting their magic, it can do the same with the vaccine." Both the vaccinated living ponies that were exposed the plague and the already infected ones are steadily turned into dead beasts while fully retaining their intelligence while being rendered insane by the pestilence's influence."

"That..." Rainbow was almost at loss of words.

"Also," Moon continued. "Contrary to what Spifire said, Celestia had made indeed a test on a infected pony that was about to become a zombie and seemed to be ok... But after three days, the patient started to change on his own but with different results."

"We were salvaging the ponies who tried to survive this horror for three days," Spitfire retorted. "When the zombies had bitten us during the rescue of, the vaccine seemed to work. We thought to be alright... But in the third day after we had returned, I felt my body becoming cold, being painfully tore apart for little bits. And then, a unbearable hunger took over and... I ate a living animal... I couldn't stop."

"No way..." Rainbow murmured in shock.

"In other words, the cure backfired." Moon replied bluntly.

Hearing that, Spitfire laughed as she considered his statement as a joke before angrily saying. "Backfired doesn't began to describe it. It's also your fault!"

"Spitfire..." Rainbow said hesitantly. "You are the one... Who spread the plague in Cloudsdale?"

"Not directly." Spitfire said nonchalantly. "Ask to Meadow. She was in the hospital after I had bestowed my gift to her."

"W... What gift?" Rainbow demanded, looking at Meadow with a worried face.

"Be grateful that I didn't had bit you." Meadow said as she looked on the floor before letting out a pained moan, getting Rainbow's attention. "I think you are going to see that by yourself."

"Meadow, don't tell me...!" Rainbow exclaimed.

What followed was the color of Meadow's pink fading and some parts of her body melting, opening some wounds and exposing some muscle, a few bones and some pale veins. Meadow lifted her head and looked at the remaining two healthy ponies, grinning insanely and looking at them with her now white, dead eyes.

Rainbow refused to accept what she has just saw. She couldn't. And yet... That doesn't change anything.

"Rainbow, don't even think I like what I have done," Meadow said half apologetic. "Yes, I was the one who infected the the patients and the others."

"But... WHY!?" Rainbow shouted.

"Spitfire asked me to do so... After she bit me." Meadow replied tranquilly.

"I just need to create a incident to balance this city," Spitfire explained. "My reason is a simple one: A general clean-up of the useless ponies and a reduction of the population."

Rainbow refused to believe what she heard from her. "You didn't mean that, right?"

"Rainbow, we cannot save all of the ponies," Spitfire retorted. "One day or another, our food will run out very quickly. And I would had infected somepony due to my newfound hunger for the living beings, soon or later, so I won't even bother to continue to lead the situation normally. I even had to devour the flesh of the first non-vaccinated pony that I had ever infected to prevent it to became a zombie and going on loose... But that was only a temporary solution."

A newfound sense of nausea struck her stomach as her mind registered the meaning of the last thing that Spitfire said. She then looked at her bloodstained neck and then understood.

"I.. I can't believe this." Rainbow stuttered in horror, covering her mouth with her hoof.

"I wasn't even thinking straight when I had committed that act," Spitfire admitted. "Still, my plan to use the vaccine to cure the infected ponies? Completely useless. You saw what happened to us and you have also saw the corruption of the Wonderbolts as you know. And yet, that can be our bliss and a alternative. A alternative called... Immortality."

"Spitfire... You need to stop." Rainbow said, freaked out.

"The harvest of the population didn't consist sorely in the elimination of few ponies," Spitfire continued. "In fact, this unbearable hunger is a real curse. To compensate this, the inhabitants, the rescued one and even the zombies can be also useful as, I can't believe I'm using this term... Food stockpile."

"WHAT!?" Rainbow flinched disgusted by that.

"I have a reason for that. When we ate our victims, our wounds healed themselves. It worked wonders." Spitfire smirked widely. "But that wasn't the only plan. In fact I wanted to spare the few ponies that are really worthy to live. So I want to give you a opportunity, Rainbow."

"I don't want know what it is." Rainbow retorted.

"Right now I just want... Sunk my teeth... On your tasty flesh," Spitfire admitted with crazed tone. "However, I feel generous. What you had to do is become one of us. I'm asking you because I want to keep our kind alive in the best I can and I won't allow the mistake of a Princess to kill them!"

"You want the ponies who trusted you to become monsters!" Rainbow said furiously.

"That... Sucks..." Spitfire said before growling in disappointment. "I guess that being the Element of Loyalty means being loyal to your still living friends. Very well. I guess I made a mistake trusting you. You can even die for what I care, you coward! But at least die by making yourself useful. By becoming our next meal."

The undead Spitfire raised her hoof, and the curtain rose, revealing other seven members of the Wonderbolts being turned into Undementias, forming a wall of crazies.

Unable to remain calm, Rainbow Dash took a few steps back. Spitfire and her other subordinates walked menacingly toward her and Moon, who remained immobile.

"Spitfire, this is not you! You can't do this!" Rainbow shouted.

"Rainbow Dash, just get ripped apart with dignity," Spitfire said with a bloodthirsty tone. "You know how this will end."

The frenzied pegasi are getting closer and closer to the two. Rainbow mentally cursed the fact that she couldn't fly. Spitfire's group was about to pounce.

But before they could do so, a invisible force smashed through the metal doors. As Rainbow and her aggressors looked at the opened entrance, Moon proclaimed.

"About time."

Author's Note

In the next chapter we have the real hero.