Disclaimer: Unfortunately not mine.

Prompt: Imagine your OTP in a universe where everything is the same except for one thing: their personalities are switched.

The Vending Machine

Touma stared at the vending machine in despair when he finally realized that it ate his 2000 yen. Already, he could feel the tears brimming in his eyes.

'Such misfortune!'

But before he could wallow longer, a hand began pushing him from the side and then a voice, "Oi, if you're not gonna buy anything then move. I need to rehydrate too, you know."

He turned his head and blinked, seeing that it was a girl who was pushing him. He took a second to study her appearance. She had short hazel hair and hazel eyes, with good looks that didn't need make-up. She was wearing a uniform he didn't recognize, but she was looking at him in a way that made him realize that she probably knew 'Kamijou Touma' before he lost his memories.

At the same instant, he realized how familiar she had acted with him and that her hand was still holding onto his arm. He also began to take note of their proximity and felt her cheeks become warm.

"W-w-w-what are you d-d-doing?!" he stuttered out.

She lifted an eyebrow at him, "Weren't you listening? I wanted to use the vending machine."

"B-but y-y-y-you're—"

"Oi, are you alright? Your face is red," she pointed out, releasing his arm to reach out and touch her palm to his forehead. He stiffened, feeling more blood rush to his face, "Whoa, you're really warm. Are you getting dehydrated or something?"

"Of course not!" he jumped back, away from her touch. He took a defensive stance while she gave him a puzzled look. Was he acting weird? Doesn't the real Kamijou Touma act like this?

It was only after that thought that he realized he didn't know her name.

Hesitantly, he said, "Wait... who are you again?"

She stared at him for a long second before she gave him a look of disbelief. "Oi, oi. Seriously? If you don't even remember my name after all our meetings, I'm going to be really upset."

"U-uhm..."

"Ah, whatever," she let out a mixture of a groan and a sigh, turning back to the vending machine, "It's Misaka Mikoto. Really, remember it for once, you idiot."

"Misa...ka...?" he mumbled to himself, trying to test her name in his tongue. Silently, he noted that even though it was the first time he heard of her, her name easily rolled off his tongue. He wondered how close she was to 'Kamijou Touma'.

She had her chin cupped between her thumb and forefinger as she looked at the selection of beverages. He recalled she wanted to use the machine and immediately warned her, "That vending machine eats money, you know."

"I know," she replied, putting her hand inside her pocket and taking out a few coins, "It only eats bills though so coins would be fine." She told him as she slipped some 150 yen in. Then she paused and turned to him, "You want some? You look like you need some juice. Your face is still red."

When she pointed it out, he felt himself blush again. He immediately put a hand on his face to cover his cheeks, mumbling instead, "You should've told me that earlier..."

"Hm? What was that?"

"Nothing..."

She studied him once she got two cans from the evil-money-eating machine. He avoided her critical gaze, feeling somewhat exposed by it. But then she suddenly smiled, "It ate your money, didn't it?"

"..."

She began snickering, "That's how you knew this thing eats money, am I right?"

"It was an honest mistake!" he defended, his face burning, "How was I supposed to know that it'll eat my 2000 yen?!"

"..."

"..."

"BWAHAHAHA! You—you put—pfffft, you put 2000 yen into a vending machine?"

"Shut up! I didn't have any change!"

"You could have—haha—there's a store at the corner of the street."

"Fine! I made a mistake. Just stop laughing, will you?!" more giggles was her response, "Well, what about you? You must've lost your money to this vending machine too, right?"

Her laughter abruptly stopped, "Heh?"

"You know this thing only eats bills. You must have experienced it first hand, right? So? How much did it eat?"

She averted her gaze, unwilling to reply.

"Oi, you know how much money I lost. It's only fair that you tell me."

"...ten thousand yen."

"..."

"..."

"BWAHAHAHAHAHAHAHAHAHA! TEN THOUSAND YEN?! I CAN'T BELIEVE YOU PUT IN THAT MUCH!"

"Oi!"

"AND YOU—AHAHAHAHAHAHAHAHAHA—I CAN'T BELIEVE YOU'RE SUCH A HYPOCRITE!"

"OI!"

His laughter halted when one of the juice cans she was holding burst out. He looked at her with a surprised expression when he saw sparks dancing around her body. Suddenly, he realized, "...an Electromaster..."

She didn't seem to hear him because she was frowning (pouting) unhappily at him. "Ugh... great. Now my hand feels sticky. I'm not buying you another juice, just so you know." She declared as she threw the broken can into the trashcan.

He watched as she opened her own can and asked, "Do you always go Biribiri when you're upset?"

"My esper power is easily affected by my emotional state so yes, the next time you laugh at me, I can't promise I won't accidentally shock you. Prepare your right hand next time."

His eyebrow rose, "You know about my Imagine Breaker?"

"So that's what it's called. Of course I know about it. How many times do you think we've battled? I even got better at hand to hand because you keep making me fight you."

"...I ask... a middle school girl to fight?" he whispered dreadfully, 'What kind of messed up person was I?'

"Aaahh~" she let out a pleased sigh when she finished her drink, "Now that was refreshing! So what now? Are you planning on fighting me again? I'm a little tired though so I'll probably decline. Besides, I feel like wandering around right now. Wanna come with?"

He blushed lightly at her invitation. It almost sounded like a date. He shook his head, getting rid of the thought. 'No way. She just wants to hang out.' "Sure, Biribiri."

She let out a sigh, "You know, that nickname is probably the reason why you don't remember my name."

At the Hospital

"Hey, you awake?"

When Touma opened his eyes the second time, he was completely unprepared to see Mikoto's face in such close proximity to his.

His eyes bulged open, and he probably would've jumped if he could. But when he made such sudden movements, he felt pain shooting through multiple parts of his body, leaving him hissing.

"Whoa there, you shouldn't get excited. You have a lot of injuries." She told him gently, helping him go back to a comfortable position on the bed. Once the pain had somewhat subsided, he sighed in relief, and she smiled, "You okay now?"

"Y-yeah, thanks..." he told her, blushing lightly.

She shook her head, "I should be the one telling you that." He met her eyes as her gaze softened. "I'm not even exaggerating when I say you saved my life...each of my Sisters' lives." She gently took his hand in both of hers, squeezing lightly, "Thank you, Touma. I wouldn't be here right now if not for you."

He felt blood rushing to his face at her actions, feeling strange yet oddly soothed with her holding his hand. "I-it's nothing. I d-d-did it because I wa-wanted to. You d-don't have to t-t-thank me..."

She smiled at this, "You would say that, huh?" she let go of his hand and he felt slightly disappointed. She then brought out a small paper bag and said, "I bought you cookies. I just took the most expensive looking ones so they shouldn't be that bad."

"C-cookies?"

"Yep. Think of it as a thank you gift."

"Y-y-y-you didn't need to d-do that! A-and you said they were expensive!"

"Well, I already bought them."

"I-I can't t-take those! It's too much!"

"They're just cookies. It's nothing big." She repeated before pointing out, "Hey, your face is red. Do you have a fever?"

He felt himself burn when she touched her (soft) hand against his forehead to check his temperature. She must have noticed that he became redder because she frowned, cupped his cheek and leaned her face closer to his.

'N-no way... is she going to—!' He couldn't even finish the thought because of her proximity. He shut his eyes as he felt his heart thunder, waiting. But then, he felt something touch again.

Braving to open his eyes, he realized her forehead was against his. Her eyes were closed as she said, "You don't seem to be running a fever, but we can't be too careful." She leaned back, and he let out a breath he hadn't known he was holding. "I'll call for a nurse, just in case."

"N-no!" he grabbed her hand, stopping her from pushing the nurse call button, "I'm fine, really."

She gave him a serious look, "Are you sure?"

He nodded and did his best to smile, "Positive." She agreed reluctantly, and silently, he told his heart to stop hammering in his chest; it was hurting his broken ribs.

"Anyway, you should try these," she settled the paper bag containing the expensive cookies on his lap, "If they're no good, I'll just buy another one."

"Y-you don't have to spend so much money to thank me, you know," he told her while mentally patting his back for not stuttering as much as before. He was honestly touched that she even went out of her way to buy him anything. But if she was giving him cookies anyway, wouldn't it be better if they were homemade?

"Hm... so you'd prefer homemade cookies then?"

He blushed again when he realized he was talking out loud, "I-I-I-I didn't say—what?"

She just smiled in response, "Alright then. I promise I'll make you some. But take these cookies anyway. It's not like I have anyone else to give it to."

The Cookie Scene

"Such misfortune..." Touma mumbled as he made his way home. Trudging on his crutches, he tried to ignore the slight pains that the tenuous movement causes his body.

It was getting dark. The sky was already painted with a light orange hue and in a matter of an hour or two, it would be night. In his state, he'd barely make it in time.

"If only checking out was quicker," he mumbled, recalling how Heaven Canceler had insisted he stayed for at least another few days because of his injuries. Luckily, he was able to convince the doctor when he mentioned the bills, and signed his release papers. The nurses were quite skeptical though and had to be convinced before they finally let him out of the hospital.

Ugh. If only Index could feed herself...

"Oi! What are you doing here?"

He looked up to see Mikoto running towards him and holding a small paper bag in one hand. "Eh? Me?"

"Yes, you," she said as she stopped in front of him, "Shouldn't you be staying in the hospital for a few more days?" she asked, frowning at him.

He merely let out a sigh and replied vaguely, "Well, us commoners don't have the luxury to stay idle for long periods of time. It's serve or be eaten in our lives."

"Huh..." her expression showed that she was confused and curious at the same time but let the matter go without further questioning.

"What are you doing here, anyway? Your dorm is the other way, right?"

"I'm here to visit you, idiot. Isn't it obvious?"

He felt his cheeks warm up at her statement, "Y-y-you didn't h-have to, you know. I actually liked the peace and quiet."

"Yeah, I guess that's nice after everything that has happened to you lately, huh?" she agreed with an understanding smile, "I didn't want to disturb your rest, but I wanted to give you these."

She held out the little bag she had been holding. He took it carefully with his right hand and studied it for a moment, noting the teddy bear themed sticker that was holding it close. "What's this?"

"Homemade cookies," her words made him blush again, "I promised I'd make you some, didn't I?"

"W-what the—you didn't—! I-I mean," he stuttered, feeling unbelievably flustered at the turn of events, "I was joking back then! I-I-I didn't really want some!" He said that but he was still holding onto the bag of homemade cookies.

She tilted her head slightly and told him, "Really? Oh well, I already made them. Take them anyways. Plus, I tried my best to bake those so enjoy them, okay?"

He could feel himself blush harder but succeeded on replying calmly, "O-okay... then I'll happily eat them."

She gave him another one of those smiles that never fails to make his heart skip a beat and said, "Anyways, if you're going home, I'll accompany you. With your current state, you won't exactly be able to run if you somehow find yourself in another mess."

"I-I can take care of myself!"

Author's Notes:

lol the prompt was from tumblr and omg, i couldn't get rid of the Touma is a tsundere idea XDDDD so yes, i think this is how the Sisters Arc will change if Touma and Mikoto switched personalities. DON'T THROW YOUR SHARP THINGS AT ME!

ah, but what else to say? I officially declare Saten Ruiko as the Number 1 Kamikoto shipper in the To Aru verse. Seriously, she beats even Misaka Misuzu in my opinion XDD omg that scary smile she gave Mikoto XDDDDD at least now it's canon that she matchmakes the two. it's so glorious!

To Aru Science Fun fact:

Touma shouldn't be able to stop Mikoto's railgun regardless of what the manga and other official releases say. I discussed it with a friend here in FF and I would like anyone in the fandom about to write something connected to this to know. You can follow the manga though it would be scientifically incorrect XD

ALSO, Railgun does not have recoil. Don't listen to people who hasn't studied electromagnetics and assumed it without researching. Seriously.

Sorry, those inaccuracies are just getting to me. I could list all scientifically incorrect things that writers in this fandom and the LN itself has made but it would make my author's notes longer than the actual story

On an end note, please do your research first before you write stuff like these. I'm pretty sensitive with it and some other people too

Anyways, thanks for reading! I hope I'll see you again!

~61wisampa