AN: The season finale of Railgun S was so awesome, more than I could have hoped for to be honest. I'm really happy about it, especially all of the mikokuro which J.C. Staff has been spoiling us with heh. First of all, I would like to thank Cun-sensei for giving me some pointers for this chapter. Please read and review.

Answering questions below:

Fortis499: Hello, hi thank you for the review! As stated in the authors note of chapter 1, this will be Mikoto/Kuroko romance and Touma/Kuroko friendship.

The Darkbringer: love triangle? Heh maybe in a sense. But you'll see what I mean in future chapters.

Metroidvania: Thank you for another long review! You know how much I love them I see heh. Ah wouldn't that be fantastic? 20,000 plus clones all in love with Kuroko, I would pay good money to see that. but you're right, the clones won't have to steer clear of Kuroko this time around and hey maybe we'll see some adorable interaction between Kuroko and a few of them. However that won't be for a while now…

TheGaarth: Thank you for the compliments! As you know, all the support is truly appreciated. As for you question, unfortunately I do not plan on having Kuroko and Touma romantically involved. Despite the fact that her mind is wiped, I consider Kuroko a lesbian and Touma is an honorable fellow and wouldn't be romantically interested in a girl so much younger than him. However, the feelings that Kuroko and Touma develop for one another, while they may not be romantic, are extremely strong. They will be strong and somewhat intense and they will be special to one another in a way that doesn't need romantic connotations in order to be meaningful. I hope that you will stick around to see exactly what I mean by this.

Dark0w1: I do have to wonder what Kuroko will think of Touma's harem! Seeing as of right now she doesn't think much of him, especially in terms of looks.

xxBakaAkki: your review made me think a lot and I realized that you were completely right. Kuroko doesn't show up much in the novels which gives me a wide scope in imagining what exactly she's up to while Mikoto is off helping Touma with his adventures. Because of your review, I decided to change how Kuroko ends up at her final destination. She's her own person so it'll be interesting to see things in her point of view instead of having her standing directly beside Touma or Mikoto (though in some instances she will be doing just that! mostly because it'll be unavoidable.) thank you for your words you really inspired me this time around.

61wisampa: out of the loop!Mikoto is going to be an ongoing theme in this fic so get ready for a bumpy ride!

PML7: The sisters arc precedes the same with a few tweaks here and there. You'll see what I mean after reading the chapter!

IdaPhantomhive: hehhh I can only imagine Kuroko's reaction to finding out she use to be in love with Mikoto. No one has had the nerve to bring it up to her yet but we should see it soon!

Draco the Spirit Dragon: The romantic/sexual tension between them will always be apparent even though instead of Mikoto being unaware of it, they both are! I think it'll definitely lead to some fun situations.

To everyone else, thank you so much for your reviews. Sending virtual love and hugs to all of you. Thank you for supporting me through this. It's your kind words that keep me inspired to continue writing.

chapter dedication: my new beta Touzen for enthusiastically tackling through the challenge that is my writing.


Chapter 6

Level 6 Shift (Sisters)

Tokiwadai's Exterior Dorms

August 20th

8:32PM

Kuroko stepped into her dorm room with a sigh. Looking around, she saw that it was, of course, empty. Despite knowing that she would be the first one home, Kuroko couldn't help but feel a little disappointed that Mikoto wasn't there to greet her. With another small sigh, she closed the door behind her.

She took off her shoes in the entry way and walked over to her bed before falling face forward onto the sheets. She covered a tiny yawn with her hand before curling her fingers into her pillow.

Kuroko spent a few minutes tossing and turning before she sat up with a frustrated huff. Her earlier elation had dampened. Though everything with Mikoto-senpai seemed okay, an overwhelming sense of dread kept Kuroko from being able to relax.

Despite how happy Mikoto appeared earlier, something told her that whatever problem her senpai was dealing with was far from over. It had been naïve of her to think the situation had been taken care of when she didn't even have any proof.

She stared up at the ceiling as her mind wandered back to that afternoon; Mikoto had seemed so cheerful talking to Kamijou-san. How she was able to let loose with him like that and held nothing back, never once concerning herself with the consequences; she never thought she'd find herself envying Kamijou-san.

Mikoto's behavior had been appalling, yet something about it had appealed to her. Her senpai had never shown that side of herself to Kuroko before. For Mikoto to be able to be so frank, open and honest with Kamijou-san…it made Kuroko a little sad.

I still don't know anything about her do I?

The sound of the lock rattling roused Kuroko from her thoughts and she shifted her gaze to the door before scrambling from her bed. She planned to greet Mikoto with a smile only to falter at the melancholy that lingered about her senpai's face. Mikoto looked at her with empty eyes and Kuroko felt her breath catch.

"Ah, Kuroko…sorry, I'm a little late." There was a slight quiver in Mikoto's voice as she lowered her eyes back towards the ground. Mikoto smiled a little. "There was this item I was trying to buy, but by the time I got to the store it was sold out."

A small watery laugh escaped Mikoto's throat and Kuroko swallowed back the sudden urge to cry. Straightening up, Kuroko cleared her throat. "It's okay, Senpai, I only returned home a few moments ago myself…" Frowning, she took a hesitant step forward. "Senpai, I—"

"Sorry, Kuroko," Mikoto interrupted with a small smile. "I'm kind of tired and I feel gross too. I think I'm going to shower." She moved past Kuroko and towards the bathroom. "I don't feel like dealing with the dorm mistress tonight. If you could please handle that I'd be grateful. Thanks."

Kuroko flinched as Mikoto slammed the bathroom door shut. Her shoulders dropped about six inches, Longing like she had never felt before coursed through her. And mixed in with that longing was a stifling feeling of uselessness. More than anything, she wanted to be of help to Mikoto; yet she also didn't want to burden her more than she already had. She couldn't even provide Mikoto comfort without falling short.

A minuscule part of Kuroko thought it would be best to simply wait things out. To trust that Mikoto knew what she was doing and that she could handle the situation. She thought that it was the right thing to do. That her role was to silently support Mikoto and not be a hindrance to her in her goals.

However, another part of her, an even larger part, couldn't help but ridicule that way of thinking. To stand idly by even though it was obvious her friend was suffering…

Just what kind of person did that make her?

Her hands dropped to her sides, fingers curling into fists as she clenched her teeth. Why was she so weak? Even now, as empty as she was, why did these crippling emotions stop her from taking action?

Why did it feel like that the remnants of her past self were holding her back from something?

She just couldn't understand it. Her stomach roiled in disgust at her complacency and her fists trembled as she held back a sneer.

If there's anything that I can do to help…no even if there is nothing, standing by like this. Her eyes squeezed shut as she gritted her teeth. Why won't I try to help?

Tears welled up in the corners of her eyes and she let her shoulders slump. What's wrong with me?

Despite all of her prattling and reassurances, she really was nothing but a coward. Always running away and denying things that were too hard to handle. Clinging to an idea of things without actually doing anything to earn it; waiting for Mikoto to come to her when she hadn't put forth any effort. Just what kind of person was she?

She held up her clenched hands and slowly loosened her fingers. Angry red marks had been left by her fingernails. Disregarding the pain, she tightened them back into fists.

No matter how weak I am, no matter how useless and empty I may be…I do not want to be the kind of person who does nothing as my friend suffers. I'll do everything in my power to help her even if she doesn't want me to. That's the person I, Shirai Kuroko, truly want to be.

With this thought in mind, Kuroko reached into her skirt pocket and dialed #2 before holding the phone up to her ear. The speed dial was set to 'Kamijou Touma' and she only had to wait a few seconds before he answered.

"Ah, hello?"

"Kamijou-san!" Kuroko practically shouted before lowering her voice in case Mikoto heard. "Did something happen with Mikoto-senpai after I left?"

"Um, not really. Misaka did get kind of weird when her twin sister showed up though. Not that she wasn't weird before but—"

Tuning him out, Kuroko's eyes slowly widened. Her heart beat loud in her chest as his words played over and over again in his head. Twin sister? She had no idea; Mikoto had never said anything...

She felt her hands start to go numb. I really don't know anything about her... Kamijou-san complained for a few more minutes, briefly mentioning that Mikoto-senpai's little sister helped him carry his drinks home in the middle of his tirade before mumbling about how he thought Misaka Imouto was a little strange but seemed like a nice girl.

"Apparently she's also training for Judgment! Did you know anything about that, Shirai-san?"

After ending her conversation with Kamijou-san, Kuroko turned to stare at the bathroom door questionably. If Mikoto-senpai had a twin sister who wanted to become a Judgment officer, wouldn't it make sense for Mikoto to tell, if not her, then Uiharu? Something about this didn't sit right with Kuroko.

For some reason, she thought back to the conversation that she had with her friends two weeks ago. Though Kuroko tended to ignore rumors, it didn't change the fact that she had heard some. One in particular stood out in her mind.

In the past few weeks, rumors of cloning a level 5 had become increasingly prominent. At the time Kuroko had quickly dismissed it, taking it as nothing more than childish nonsense. However, looking back on it, Mikoto's nonchalance regarding the whole matter was slightly…troubling.

If she remembered correctly, Mikoto had been acting strange that day as well. Her answer to the particular question had been even stranger.

"If I suddenly met my clone? I wonder…honestly, I'd think I'd feel sick and want her to disappear."

Kuroko frowned. There's no way… but still, I can't shake this feeling that maybe…Kuroko sighed as she placed her hand on her chin and considered her options. Even if they're nothing but baseless rumors it couldn't hurt to check them out right?

She kept to herself even as Mikoto finally emerged from the bathroom and they went about their normal routine in silence. An hour later, after taking her own shower, Kuroko found herself sitting at her desk pointlessly re-brushing the same section of hair as she stared unseeingly at the blank document open on her screen.

"Kuroko?"

Kuroko started and turned towards Mikoto curiously. The older girl was hunched over on her bed, sitting Indian style as she picked at the bed sheets. Kuroko stared at her trembling back for a moment and felt her heart ache before she whispered a soft. "Yes?"

"It's just, uh." Mikoto's voice shook a little, followed by a tiny laugh. "I'm sorry I haven't really been around these past few days."

"T-that's quite alright, Mikoto-senpai!" Kuroko made sure to put just the right about of cheer in her voice. "I understand that you have other matters to attend to. I've been getting by."

Mikoto huffed a little as she lifted her knees to her chest. "I can see that." she grumbled. "What with you hanging out with that guy…h-hey," Mikoto brought her hand to the back of her neck and nervously rubbed it. "Do you see that guy often?" her voice lowered. "D-does he make you happy?"

Kuroko bit her lip as she frowned, unsure how to answer. She thought for a moment before hesitantly responding. "Um…though, I am not sure why you are asking me this, yes. I consider Kamijou-san a friend."

"That's good. I mean, uh, that you have him." Mikoto gave an awkward smile. "I know I've been absent lately, so it's good that you have someone."

"I suppose so…" Kuroko mumbled as she placed her hands on the back of her chair and turned to face Mikoto fully. Though she couldn't see Mikoto's face, she could tell that she was upset. Her grip on the chair tightened a bit.

Just hold on a little longer Mikoto-senpai…

She took a deep breath as she stood before cautiously walking over to Mikoto's bed. "Anyways, it's getting late." She started as she placed her hand on Mikoto's shoulder, drawing the older girl's attention away from the covers and onto her. She smiled at Mikoto as her eyes softened. "You look like you could use some sleep, Mikoto-senpai."

"What? I-I'm not tired though." Mikoto muttered back unconvincingly as she shifted her eyes to the side.

"No arguing!" Kuroko pushed Mikoto back onto her bed, giving her a stern stare when she attempted to sit up before smiling when she lay back down with a roll of her eyes. Kuroko lifted her covers around her senpai before patting them with a grin. "Even if it's only for a few hours, you should rest."

Mikoto rested her head on her pillow as she glared up at Kuroko with a mix of grateful annoyance. "I don't know how I feel about you bossing me around."

"I am simply concerned with your well being, Senpai." Kuroko said importantly as she set Kirugumar next to Mikoto before straightening up and placing her hands on her hips. "It would make me feel better if you did."

"Ugh, Kuroko…"

She's so stubborn. Kuroko held in a sigh as she gazed at Mikoto affectionately before her lips curled into a small grin. This is cheating but I am sure she can forgive me. With that thought in mind, Kuroko cleared her throat before placing her hands behind her back and leaning down until she and Mikoto were only a few inches away. Kuroko brushed a strand of auburn hair behind her ear as her voice grew gentle. "Please, Mikoto?"

Mikoto's eyes swirled with an unreadable emotion as they widened in surprise before softening a moment later. She returned Kuroko's smile with one of her own. "Fine...but just this once."

They stared into each other's eyes for a moment before Mikoto ended it with a sigh and turned onto her side. She snuggled into her stuffed bear as she mumbled, "Goodnight, Kuroko."

Kuroko lingered by her side for a moment, almost tempted not to leave. Then, with a sigh, she flipped off the light and got into her own bed. She laid face down and stayed that way until she was sure that Mikoto was asleep nearly an hour later. Kuroko sat up with a deep breath, quietly slipping out of bed and moving to her desk. She reached inside the drawer and pulled out her phone. After searching through her contacts, she lifted the phone to her ear and waited for a moment before visibly brightening when the person on the other end answered.

"Ah, I know it's late but I was hoping I could come over."

At the response, she nodded, smiling a little. "Thank you. I'll be there soon."

.

.

.

"Thank you for allowing me to come over so late at night, Uiharu," Kuroko said sincerely as she stood beside Uiharu's seat. Initially, Kuroko had planned to handle everything by herself. She wanted to avoid worrying her friends at all costs and she didn't want to lose Mikoto's trust by involving other people in her affairs.

However, as she was lying in her bed waiting for Mikto to fall asleep, she had realized that there was only so much she could do by herself. How much information could she truly gather if Mikoto herself was trying to keep something from her? Though she personally could not remember, she did dimly recall Uiharu saying that Mikoto-senpai was almost as good of a hacker as her.

Kuroko was adequate at operating a computer system, but not at Uiharu's—and apparently, Mikoto's—level. So who better to ask than the person who claimed they could beat the electromaster?

Which was precisely the reason she was here at her friends dorm at almost eleven pm.

Uiharu tried talking around the taiyaki in her mouth. "Ish no problem, Shirai-shan!" Then swallowed the last bit and grinned up at her. "I'm used to you making me get up at random hours of the night to help you with something."

"Oh." Kuroko responded dryly, wondering just how often she took advantage of this girl's kindness. "Well, still, thank you. I really appreciate this."

"I'm actually not used to you thanking me either." Uiharu giggled as she pulled out her laptop and set it on the table. "But you're welcome, Shirai-san. To be honest, I sort of missed this, so I'm happy to be of help."

Smiling a little, Kuroko leaned down until she and Uiharu were eye level and placed her palm next to the computer. "That's good to hear." Kuroko mused, watching Uiharu boot up the computer. A few minutes of silence passed before Uiharu tilted her head towards her.

"What exactly are we looking for anyways, Shirai-san?"

"Anything in relation to the mysterious fires at those factories throughout the city." Kuroko paused before continuing. "Actually, if you could narrow it down to the occurrences between the dates of August 15th through the 18th that would be helpful."

"Gotcha."

Kuroko frowned, her eyes flickering between the various images on the screen. "Can you hack into Shinaame University's mainframe?" she inquired, noting that the first listed fire occurred at Shinaame's DNA Map Analysis Laboratory. If her theory was correct and Mikoto-senpai was the one causing the fires, then there should be some evidence stating that.

"Huah, of course I can, but what for?" Uiharu squinted, pulling up the website and typing in a few codes.

"Just a hunch I have." Kuroko crossed her arms as she watched the other girl work. It took Uiharu under a minute to hack into the mainframe and Kuroko released an impressed whistle. She had to remember to ask Konori-senpai about exactly how skilled Uiharu truly was.

Kuroko skimmed the lengthy report filed in the University's mainframe before her breath caught. "Wait." She pointed at a small line of text. "Click there."

She leaned closer to the screen as she re-read the sentence. It appears that the reason of the fire was an electrical disturbance in the laboratories mainframe.

Electrical disturbance.

Normally a sentence like that wouldn't have set off any red flags but Kuroko was mindful of Mikoto's ability. Objectively speaking, while it was circumstantial evidence at best, it did nothing more than cement the truth for Kuroko. She didn't know why or how, but Mikoto-senpai was the one attacking those labs.

Though the fact that she hasn't been caught yet is…Kuroko frowned once more as she straightened up, placing a hand under her chin thoughtfully. More importantly, what is happening in those labs? Does it have anything to do with those so called "clones?"

"Is something the matter, Shirai-san?" Uiharu tilted her head, looking back at Kuroko. Kuroko responded to Uiharu's worry with an easy smile, shaking her head as she sat down.

"No, everything is fine, Uiharu. I just remembered something important but it's not relevant to the matter at hand."

Uiharu frowned, obviously confused. But it didn't seem like she'd manage to catch on and Kuroko released a small sigh of relief. She propped her elbow on the table as she returned her gaze to the computer.

"In any case, let's continue our search, shall we?"

.

.

.

August 21st

Tokiwdai's Exterior Dorms

7:17PM

Kuroko sighed heavily onto Mikoto's desk, her cheek pressed against the cool wood as she stared bitterly up at the blank screen. She had spent most of the night with Uiharu carefully tracking down where each and every fire was located until they had managed to scrounge up a suitable pattern. The majority of the facilities had been doing extensive research on DNA mapping and muscular dystrophy.

Three laboratories in particular, Kanasaki University of Muscular Dystrophy Research Institution, Mizuho Organization Pathology Analyst Laboratory and Higuchi Pharmaceutical Seventh Pharmaceutics Research Center all had to be evacuated over a two week period. Coincidentally, the same nights they were evacuated coincided with the nights Mikoto-senpai didn't come home.

It seemed that all the institutions were conducting an experiment of some sort before they were shut down.

Other than that, there was nothing else connecting the laboratories to one another. Realizing that they had collected all the information they could at this end, Kuroko had persuaded Uiharu to stop looking for the night. Kuroko then spent most of the day trying to see if she could come up with any more information on her own, and even went as far as to breaking into Mikoto's computer to see if there was anything on there. (Her senpai's password was 'GekotaFan' so she hadn't needed Uiharu's assistance in that regard).

However, after logging into Mikoto's desktop, she was not surprised to find out that Mikoto hadn't kept any record of her activities.

In the end I wasn't able to find out anything…Kuroko sat up a little, looking around the empty room. Senpai still isn't back yet either. She lowered her gaze back towards the table. When Mikoto had said that she would be done with everything by today, a deep sense of foreboding had welled up in Kuroko. Her stomach had twisted with nerves and she knew that she had to try harder or else…well, Kuroko did not know what would happen if she didn't but she knew it would be bad.

Still, after searching long into the night, she hadn't been able to find anything.

Kuroko leaned back in the chair, staring up at the ceiling. What can I do? Should I go look for her? But I have no idea where to start. Her brows furrowed as she leaned further back. Senpai…

Due to her inattention, Kuroko managed to lean all the way back, so far back that she fell out of her chair and slammed her head on the floor. For a few throbbing seconds, Kuroko's mind was cleared of any troubles as she focused on the ringing in her ears. As she slowly opened her eyes, tears began to pool in the corners. She raised a hand to wipe them away, but paused when she noticed that Kirugumar was under the bed.

"Oh." Kuroko reached forward and grabbed the stuff bear. "He must have fallen off her bed sometime during the day." She stood up to place him on the bed when her hand brushed his partially open zipper. Curiosity getting the best of her, Kuroko unzipped Kirugumar and tilted her head at the papers that popped out from him.

Kuroko unfolded the bunched up papers and gasped when she noticed the title of the document.

N…no way.

Radio Noise: Accelerator's Level 6 Shift

Her hands began to tremble as sheread through the first few sentences.

There are a total of 7 level 5's, but only Accelerator is capable of reaching Level 6. Based on the Tree Diagram, we have concluded that by preparing 128 battlefields and by killing the Railgun 128 times, that the subject would shift to level 6.

Kuroko's stomach turned in disgust. "W-what the hell…Railgun? That's Mikoto-senpai right?" she clenched the papers tighter as she continued reading.

However, seeing that it is impossible to procure 128 Railguns, we've developed the mass-produced 'Sisters'

"Misaka did get kind of weird when her twin sister suddenly showed up…"

Kuroko gritted her teeth as she recalled Kamijou-san's words from earlier that day.

By eliminating 20,000 'Sisters', who were deemed level 3, Accelerator will reach level 6—

The sound of the doorbell ringing pulled Kuroko's eyes towards the door. Small shivers wracked her body and she felt the urge to retch but she could only clench her hands. The doorbell sounded again and Kuroko forced herself to move towards the monitor.

Her eyes widened when she saw who it was.

"Um, hello? Is anyone there? That's weird; did I press the wrong number…?"

What's Kamijou-san doing here? Her hands dropped to her side. She watched him glance around in confusion for a few moments, then pressed her finger against the 'talk' button.

"Kamijou-san?"

"Ah, Shirai, is that you? Is Misaka-san there?"

Why is he asking for…? Kuroko's mind raced a mile a minute. She swallowed before responding. "Mikoto-senpai is not home yet, but…you can come up, Kamijou-san."

"Are you sure?" Kamijou-san looked around anxiously once more. "Are boys even allowed in your dorms?"

"If you were actually worried about a thing like that then you should have called ahead." Kuroko glared at the screen. "Just hurry up."

.

.

.

Kuroko opened the door for Kamijou-san and ushered him in, looking at both ends of the hallway to make sure no one saw. When she was sure he hadn't been spotted, she hid the documents behind her back as she closed the door and leaned against it. She searched his face for some kind of explanation, but something in his eyes made her stomach twist.

"Kamijou-san?"

He looked up and smiled a little before laughing, "Sorry, it's just." He paused and scanned the room. "Do you know where Misaka is?"

"No." Her eyes narrowed. "Kamijou-san, what's wrong? And whose cat is that?"

Kamijou-san's arms tightened around the cat as he shuffled his feet, his eyes shifting nervously from side to side before finally settling on her. "Shirai-san, I…" His gaze dropped. "I think Misaka is in trouble."

Brows furrowing, Kuroko pushed away from the door and took a step towards him. "What makes you say that? What do you know?"

He licked his lips, then cleared his throat. "I saw something that I'm pretty sure I wasn't supposed to." Kamijou-san frowned. "Misaka Imouto—she," He blinked rapidly, "…I wasn't able to stop it…"

Realization settled in Kuroko's stomach like a stone. She shakily brought the documents from behind her back.

By eliminating 20,000 Sisters…

Kuroko swallowed thickly, completely ignoring Kamijou-san in that moment.

10030, August 20th 10:30pm, 10031, August 21st 6:30pm, August 21st 8:30pm…

"Kamijou-san, what time is it?" Kuroko voice shook as she gazed unseeingly at the papers.

Kamijou-san pulled his phone out and quietly read out the time. "7:30."

"Everything will be over by today..."

Kuroko didn't understand anything that was going on. The idea of killing a person 20,000 times was too insane, even for her. She couldn't comprehend it, was unable to make sense of it. But still, it did not change what she needed to do. What she had to do.

The papers fell to the floor as she rushed to pull on her shoes, her throat dry as she thought about Mikoto-senpai's words. If she had meant what Kuroko believed she did…

"Shirai-san?"

"I am sorry, Kamijou-san, I have to go." The words were barely out of her mouth before she teleported out of the room. The buildings appeared around her in a blur as she teleported across the city, her destination unknown as her heart raced in fear. She wasn't sure where she should go, but she knew she had to find Mikoto.

Before it was too late.

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.


AN: The bolded parts of the section are directly from Volume 3 of Toaru Majutsu no Index. I'm sure there are some of you who are disappointed with Kuroko not meeting a Sister this chapter but I felt like it was better for her to come to the realization about Mikoto on her own. Even without her memories, Kuroko is a smart girl and the fact that they were committing these experiments in plain daylight, the fact that the clones were allowed to walk around Academy City without much restraint and the fact that Mikoto didn't exactly cover up her tracks when destroying the factories leads me to believe that people not finding out about the experiment wasn't on the scientist high list of priorities. Though it would have been fun to have Kuroko meet a Sister this time around, I didn't want there to be a 'butterfly' effect as you may call it seeing as the only real opportunities at this point to meet one is if she were with Touma.

Next chapter!: The infamous bridge scene and Accelerator makes his debut!