I am borrowing a complicated world and although I tried to explain things, there may be some nuances that are confusing. If you are unfamiliar with A Certain Scientific Railgun, you can read Wikipedia or watch the first couple episodes of the anime. The events of this story take place during the month before the first episode of the anime, but after Mikoto Misaka and Kuroko Shirai had become roommates.
“Stop running away, Sissy!”
Kuroko Shirai chased her new roommate around their dorm room. Mikoto Misaka, the roommate, managed to keep a few steps ahead of her pursuer. The girls, both students at Tokiwadai Middle School, had been roommates for over two weeks now.
“Back off, Kuroko!” Misaka said, expertly evading the grasping hands of the other girl. Enough time had passed that she was no longer shocked by her roommate's unwelcome advances, but her annoyance only grew each time. “And I told you to stop calling me that.”
Finally the chase came to a halt with Misaka standing at the head of Kuroko's bed and Kuroko herself at the other end. Kuroko put her hands on her hips and glared at the taller girl.
“I don't see what the big deal is, Sissy,” Kuroko said petulantly. “It's not like I'm asking you to do something you shouldn't be doing on your own.”
“The big deal is my school uniform is my business, not yours.” A spark fizzed briefly in the air in front of Misaka as she returned Kuroko's glare.
Kuroko adopted a stern look and folded her arms across her small chest. “That may have been true before we became roommates. But it is my duty to make sure the Ace of Tokiwadai dresses like a proper lady, and a proper lady wears panties.”
“For your information, Kuroko,” Misaka said tiredly, “I DO wear panties under my skirt. I just wear shorts on top of them.”
“Really?” An evil glint came into Kuroko's eye. Without warning, she vanished.
Before Misaka fully registered the teleporter's disappearance, she felt a warm breath on the back of her neck. As she spun around, she felt a hand brush against the shorts under her skirt. Before she completed her pivot, Misaka felt her shorts vanish.
Misaka gasped and lashed out at Kuroko, who was grinning a foot away. Of course, before Misaka's punch could land, Kuroko was gone. She reappeared over Misaka's bed, and landed on the mattress gracefully. She watched her roommate innocently.
“I... you...” Misaka sputtered, seething. “Give me my shorts back, Kuroko!”
“Those?” Kuroko asked nonchalantly, pointing up at the ceiling fan where Misaka's shorts lay draped over one of the blades.
“Yes!” Misaka shouted.
“Sissy,” Kuroko got off the bed and put her hands on her hips. “I have to make sure you are wearing proper panties.”
“What the heck are 'proper'...” Misaka trailed off. Kuroko had lifted her skirt up, displaying the fanciest and maybe the most erotic pair of panties Misaka had ever seen. They were black panties, tied at the sides with a strip of gold lace running from her hip to her...
Misaka scrunched her eyes tightly closed, her face turning a bright shade of red. She wondered what she had done to deserve a roommate that had such an unhealthy interest in her sexuality. “P-put your skirt down!”
Taking advantage of Misaka's shut eyes, Kuroko had sneaked up behind her friend. With both hands, she flipped up Misaka's skirt. In the brief moment before she teleported, Kuroko saw a flash of white cotton panties with a cartoon frog face stamped on the rear.
“Hey-!” Misaka spun around again, her eyes flying open, but the other girl was gone. Misaka was beyond tired of Kuroko's antics, but it was difficult to fight someone who could perceive eleven spatial dimensions and vanish in an instant.
“No, no. That just won't do, Sissy,” Kuroko said from the far corner of their room. She touched a hand to her face and tilted her head with concern. “You're not in elementary school anymore. You can't go aro-eep!”
Narrowly avoiding the pencil holder which Misaka had thrown at her, Kuroko reappeared next to Misaka's bed, although on the opposite side from her raging roommate. “As I wa-aaahh!”
In retrospect, getting closer to an angry electrokinetic girl may not have been the best decision. Misaka had hit Kuroko with a bolt of electricity roughly equivalent to a taser's shock. As the smaller girl collapsed to the floor, Misaka jumped up onto the bed. She looked down at Kuroko like an avenging angel. Kuroko did not even have time to open her mouth before Misaka began zapping her again.
Keita frowned as he rifled through another rack of clothes. There was a large selection at this store but nothing had caught his eye today. He had built a reputation on daring and creativity, so he could not simply settle for traditional lingerie. Given that Academy City was comprised mostly of young students, it was a miracle that this adult shop managed to stay in business. The manager who had been following him around and giving the evil eye probably did not endear herself to many customers either.
Keita ignored the woman. He had been here often enough that she should know that he was a customer, probably the best she had. Yet she still insisted on hounding him around the store. Perhaps it was precisely because he purchased so much merchandise that she was suspicious. She probably thought he was a completely depraved teenager and maybe he was. But Keita preferred to consider himself a businessman. His clients were the depraved ones, which he did not mind at all as long as their money continued to flow into his bank account.
It had been a long and exhausting day for Kuroko. After classes she had only time for a short session before her duties with Judgment began. Judgment was a city-wide organization of students which performed tasks for the citizens that could range from keeping order to picking up trash. Today had been especially busy, and Kuroko had spent most of the afternoon trying to resolve a dispute between a store owner and his wife. Then Kuroko's homework for the next day had consumed the majority of her evening.
She was looking forward to a relaxing shower before bed. After stripping out of her school uniform in the bathroom, Kuroko inspected her petite body in the large mirror above the sink. Her pale skin was flawless except for a fading bruise where her left shoulder met her bicep. A testament to the hazards of Judgment. Kuroko reached up and untied the bows in her hair, letting it hang freely down to her back. As quietly as she could, Kuroko closed the lid of the toilet seat. Misaka was in their room outside, although she had headphones in when Kuroko had retired to the bathroom.
Kuroko bent over the small hamper that Misaka kept in the bathroom. With greed twisting her lips into a grin, Kuroko rummaged through the used clothes until she found the childish panties that had been the source of this morning's confrontation. Kuroko pressed the stupid frog face to her nose and inhaled deeply. Misaka had showered too long ago for the underwear to be warm but Kuroko could still smell her roommate's wonderful scent.
Kuroko sat down on the ceramic lid of the toilet with a shiver. It was cold and goosebumps appeared on her slender thighs as she situated herself. Kuroko brushed the fingers of her right hand against the soft flesh between her legs and gave another shiver that had nothing to do with the cold. With her free hand, she held the crotch of the panties up to her nose and breathed in slowly. Her budding chest swelled as her lungs expanded, taking in Misaka's aroma.
While she would have been happy to idly stroke her labia for hours with the panties pressed to her face, she knew that Misaka would get suspicious if she took too long in the bathroom, especially if the water was not running. So Kuroko rubbed her cleft with increasing urgency, dividing her attention between her clit and the deeper folds of her pussy. Kuroko closed her eyes. The fingers were Misaka's. The pressure on her face was Misaka's own bare pussy. Kuroko trembled on the toilet seat, her hand a blur as she coaxed herself to the pinnacle of pleasure. Her climactic cry was only stifled by gagging herself with Misaka's panties, which was blissful in its own way.
When the ecstasy was no longer overwhelming, Kuroko took Misaka's panties from her mouth. She dabbed them daintily against her pussy to whisk away the bit of moisture that her frantic session had produced. Kuroko started the shower and buried Misaka's panties back in the hamper before she stepped into the spray of hot water. Removing the day's dirt was a satisfying follow-up to removing the day's tension.
Kuroko exited the bathroom with a dramatic swirl of her short nightie. Misaka, as usual, ignored Kuroko's sex appeal. After a fruitless attempt to crawl into Misaka's bed with her, Kuroko turned off the lights and slipped under her own covers. She fell asleep quickly after the long day and her dream were filled with desire for Misaka.
Keita returned to his body and sat up in his bed. As usual, the transition from free-ranging consciousness to earthbound mortal was unpleasant. He felt a wave of nausea as his mind reconnected with his stomach and apparently decided it did not like what it found. Choking down vomit, he did a self-assessment. Everything seemed to be working properly, although he always felt slow and heavy after his expeditions. He was one of a number of espers in Academy City that have some skill related to astral projection, but none of the others described the same high level of disorientation Keita always felt after long trips away from his body. Perhaps because none of the other espers had his level of skill.
In the Academy City database, Keita is listed as a level three esper. The database is wrong. At level two, Keita could leave his own body and project his consciousness into the world, seeing and hearing everything around him as if he was a ghost. At level three, Keita could enter another person's body and sift through thoughts and memories. As far as Academy City was concerned, Keita had not developed his esper ability any further. In reality, two years ago Keita had broken through to the next tier of his power, developing skills that would have qualified him as a level four esper. With his latest abilities, Keita could take control of the bodies that he possessed, suppressing the original personality. He also developed the more subtle ability of rearranging the thoughts and attitudes of those he overshadowed, rather than simply reading them.
When he first developed his astral projection ability in middle school, Keita had been rather disappointed with it. Admittedly it could be useful for gathering information unseen, and in fact at the time Keita had gathered quite a bit of information about the interior of girls' locker rooms. The problem was it left his body completely defenseless. Soon, though, Keita realized he could leave his body right before going to bed, giving him about eight hours to roam Academy City as a spirit. While he was gone, his body entered its usual comatose state, but his consciousness stayed active and alert in spirit form. When he returned his body, including his brain, was well-rested from “sleep” and he could continue with his day. Effectively, Keita no longer needed to sleep as long as he remembered to project his consciousness before truly falling asleep. This was not as great as Keita originally thought it would be. He was able to avoid sleep, but the hours between eleven o'clock at night and seven o'clock in the morning are the dullest of the day precisely because most everyone else in the city is sleeping.
Around this time, about to graduate from middle school, Keita was a level three esper. He soon realized his nightly forays were honing his esper ability. The distance he could travel from his body increased every night until he could venture anywhere in the city. It was on one of his astral expeditions that he discovered his gift had grown in other ways. Keita had been rather predictably wandering around a few of the girls' dorms, peaking in on his fellow students as they took showers. One of his stops was the room of his prettiest classmate, who was laying on her bed as she did her homework. Keita slipped inside of her body, intending read her thoughts to find out whether she was planning on taking a shower soon.
Until that night, reading thoughts or memories was similar to reading braille. Keita would essentially press his consciousness against the mind of the person he was possessing and then interpret the impressions that were there. That night, though, when he queried the girl's mind, it shifted against him. The more Keita pressed, trying to learn whether she would take a shower, the more fluid her thoughts became. Keita was confused by the end of the process: the girl was definitely thinking about taking a shower now, but Keita suspected that thought had not been in her mind before his intrusion.
The girl sat up in bed abruptly, apparently deciding midway through a homework problem that it was time to take a shower. Keita, still possessing her, was so shocked that he flinched away, forgetting that he was not in his own body. But as Keita instinctively recoiled, the girl did too, flinging herself back down onto her bed. Keita felt confusion blossom in the girl's mind as she wondered why she had suddenly thrown herself back on the bed. Panicked, Keita pushed against the girl's thoughts again, desperately smoothing away her worry. He brushed her thoughts aside so forcefully that the girl collapsed, falling asleep in an instant.
Keita's astral form floated out of the girl and he looked down at her. She was laying in an odd position but she was breathing easily and seemed to be sleeping normally. Keita did not know how long he floated above her, watching the pretty middle school girl as she slept, oblivious to him. He did not know what he had done, although his agile mind was quickly making connections and realizing the new potential of his abilities.
After that night, Keita understood that he could probably test as a level four esper but he decided to keep his abilities a secret. Night after night he floated through the city, discovering his abilities and testing their limits. He did not have anywhere near the power or precision of Misaki Shokuhou, the level five telepath of Academy City, but he quickly learned to exercise a lot of control over the people he overshadowed. The main drawback to his ability was that he could not act in the moment, since he needed to first project his astral form into his target. As a result, most of his experiments involved brainwashing someone in their sleep and then measuring the effects the next day. A few months after discovering his level four abilities, Keita stumbled across a few message boards online that gave him an idea for a new business.
The camera flashed. Kuroko dropped her innocent expression and opted for a sultry pout. It was probably a more appropriate expression anyway. The photo shoot had been going on for a few minutes already, so Kuroko had already taken off her skirt but still had her panties and blouse on. It was hard to maintain a convincing innocent expression when you knew you are exposing yourself for hundreds or maybe thousands of men. The camera flashed again, cuing her next change. Kuroko no longer needed to be told how to pose for the camera. After almost a year, she was a pro. With a seductive smile, Kuroko hooked a thumb under the waistband of her panties, as though she meant to pull them off. She would eventually, but not yet.
During her first sessions Kuroko had asked the cameraman, Keita, why they started each photo session with her stripping out of her school uniform. She knew she had a hot little body, but it seemed like the same clothes would get boring after a while. Keita had said he liked to remind her fans that she was a student at Tokiwadai Middle School by starting each set with a few pictures of her uniform. Kuroko had shrugged and accepted that, Keita knew best after all. Perhaps he made up for her boring uniform with the outfits that came later.
