PROLOGUE

Kuroko Shirai, a Pillow, and a Bed
Suffering_of_a_Negligee.

Morning started early at Tokiwadai Middle School.

However, 5:20 AM was definitely a little too early. The birds were only just beginning to chirp at this hour, and silence normally still prevailed in the girls’ dormitories. The living quarters weren’t all the same. Eighty percent of the population in Academy City was students—so there were many different types and varieties of dorms. Tokiwadai, in particular, had annoyingly strict curfew and sleeping hours. (Though sometimes certain Level Fives or Judgment officers would sneak out.)

Everyone was fast asleep in the off-campus dormitories of Tokiwadai.

Except, perhaps, for Kuroko Shirai.

She tossed and turned in her bed. Awake but, more accurately, unable to sleep.

Usually she tied her brown hair into pigtails on either side, but not at that moment, so her hair was splayed across the bed. All she wore was a negligee—so thin and sheer, one would have to observe from up close to even notice she was wearing something—and short panties frilled with lace. You could see all the way from above her flat chest down to her navel, but she didn’t appear bothered. Not just because this was a girls’ dormitory, but because her roommate was someone special.

“…”

Abruptly, Kuroko stopped rolling around.

She looked toward the bed next to hers.

Not even fifty centimeters separated them. She was so close to the girl in that bed who was asleep, unlike Kuroko. A tiny bit of sweat clung to her shoulder-length brown hair, and her slender white fingers poked out of her baggy, light-blue pajama sleeves. She had a change of heart recently and now wore rather ornate hairpins on the side of her head, but at the moment they were sitting in a group on her nightstand.

Mikoto Misaka, Kuroko’s beloved “big sister.”

She was one of only seven Level Five espers in Academy City and one of just two at Tokiwadai. They called her the school ace, a monstrous middle school girl who drew ever more envy by the day. There she was, limp on her side in her bed.

“…Mm-heh-heh…have to do anything I say…punishment game…,” she mumbled through her cute lips, looking incredibly happy with herself for some reason.

Shirai, in her own bed, began to madly scratch at her hair with her hands. Gah, I need to know! What has been going on with Big Sister lately?! She’s been like this ever since the Daihasei Festival!! Who in her dreams could she possibly be saying that to?!

“Haah, haaah,” she panted heavily. As their feminine names implied, Kuroko Shirai was a girl, and Mikoto Misaka was also a girl. But between them, there was something else, a girlie kind of thing, sort of like, well, you know. It would be too graphic to say it straight, so Mikoto’s underclassman Kuroko had opted for the long con.

She wouldn’t have a problem if Mikoto’s sleep talk was directed at her. But she didn’t have any recollection, at least in the past few days or so, of challenging her to a punishment game. Which meant, whether it was a boy or a girl she was talking to, this was a huge problem. Those were Shirai’s super-individual thoughts on the situation.

Mikoto Misaka, who didn’t feel any of her gloom, clutched her big pillow, the one her head was supposed to be on, in her arms.

“…What should I have you do first…mm?”

You stinking pillow!! Wh-wh-why is B-Big Sister rubbing her cheek on it now?! What is that floofy pillow supposed to represent?!

Kuroko Shirai tossed and turned in her bed, but the happy girl’s eyes showed no signs of opening.

It was 5:25 AM.

And once again, she hadn’t gotten enough sleep.